However, "police often react towards the crowd as a whole" - and if people feel that the police use of force against them is unjustified, this increases their "us versus them" mentality.

Experts highlight a series of police tactics that were seen as heavy-handed - including the firing of large amounts of tear gas at young protesters - as moves that galvanised protesters and made them more confrontational.

Moral psychology can help explain why some protests turn violent, says Marloon Moojiman, an assistant professor in organisational behaviour at Rice University.

Looting and vandalism can be more targeted than you think

In the US, hundreds of businesses have been damaged, and there has been widespread looting in LA and Minneapolis over the weekend.

He says there is "a long history of targeting, or selectivity", in vandalism and looting. "In the LA uprisings, you'd often see 'minority owned' spray painted on minority businesses, so that people would bypass those."

Public order experts say that for the police, being seen as legitimate and able to engage protesters in dialogue is key.

Prof Hunt says this week's US riots are the most serious ones since 1968 - after Martin Luther King was assassinated.

She added that she wanted to avoid a situation where, "people are being told they have to go back to work and they remain in lockdown for the rest of the time - that would not give very much quality of life to people".

Meanwhile, 80 organisations from across different sectors of Scottish life have written to Ms Sturgeon calling for a radical response to the coronavirus recovery.

American tennis player Serena Williams, a 23-time Grand Slam champion, shared a lengthy post on Instagram.

Teenager Coco Gauff, who had a fairytale run at Wimbledon in 2019, urged her Twitter followers to "demand justice for George Floyd".

Liverpool striker Rhian Brewster wrote a lengthy post on Twitter: "This is way deeper than just pointing out who's staying quiet and whose speaking up."

Vanessa Bryant, the widow of basketball legend Kobe, shared an image of her husband wearing an 'I Can't Breathe' t-shirt.

Formula 1 champion Lewis Hamilton criticised those in his industry for not speaking out.

"I feel surprised and angry. An incident of this type stands out at a moment of national mourning for so many dead," she said.

Spain has among the highest number of coronavirus cases and deaths in the world. As of Saturday, the country had 239,228 infections and 27,125 deaths, according to a tally by Johns Hopkins University.

On Saturday, Professor John Edmunds, a member of Sage - the Scientific Advisory Group for Emergencies which advises the government - said the levels of coronavirus were still "very high", adding that it was a "political decision" to ease measures.

In Wales, people from two different households will be able to meet each other outdoors from Monday.

And Phil Anderson, head of policy at the MS Society, said people would "rightly want to hear a lot more about the scientific evidence showing this will be safe for them".

Widespread testing forms a central part of the government's strategy to control the virus, as it aims to ease blanket lockdown in favour of more targeted measures.

The UK's R value - the number of people each infected person passes the virus on to, on average - is currently between 0.7 and 0.9.

Near Union Square, in the heart of Manhattan, a police vehicle was on fire, sending plumes of black smoke into the air. In Brooklyn, protesters and police clashed for hours in Flatbush. In Los Angeles, a police post was burned in a shopping mall while nearby shops were looted. In Nashville, Tennessee, a historic courthouse was set on fire and in Salt Lake City, Utah, vehicles were burned and a man with a bow and arrow was arrested after he aimed it at protesters.

Social media posts showed flames and thick black smoke billowing from a fire in downtown Philadelphia, where an earlier peaceful protest ended with cars being set ablaze, and law enforcement vehicles came under attack in and Chicago.

The presumptive Democratic presidential nominee, Joe Biden, struck a different tone, calling protests against police brutality “right and necessary” but urging an end to violence. “The act of protesting should never be allowed to overshadow the reason we protest,” he said in a statement.

“We will not tolerate actions like these against New York City police officers,” the city’s police department said in a tweet announcing the arrest of “multiple people” for throwing molotov cocktails at police vehicles. The US attorney’s office subsequently announced that it had filed federal charges against three people over the incidents.

Numerous media outlets, including CNN, Reuters and MSNBC, reported that their staff covering protests in the city had been hit by rubber bullets fired at them. Media outlets and journalists in numerous cities reported being targeted by police with chemical agents or less-lethal rounds, and several reporters were arrested.

“The memory of George Floyd is being dishonored by rioters, looters and anarchists,” Trump said, speaking at Florida’s Kennedy Space Center after watching the launch of the historic SpaceX mission.

George Floyd’s brother, Philonise, said on Saturday he had briefly spoken to Trump about the death of his brother. “It was so fast. He didn’t give me the opportunity to even speak. It was hard. I was trying to talk to him but he just kept like pushing me off like, ‘I don’t want to hear what you’re talking about,’” Philonise told MSNBC.

In Atlanta, people set a police car ablaze and broke windows at CNN’s headquarters. In Oakland, San Jose and Los Angeles, protesters blocked highways and police fired teargas. In Louisville, Kentucky, police fired projectiles at a reporter and her cameraman during a live shot. Protests over police brutality and the death of George Floyd ignited once again on Friday, as Minneapolis faced another night of chaos and demonstrators clashed with police in cities across the US.

You’ve read more than 70 articles in the last six months. We believe every one of us deserves equal access to fact-based news and analysis. We’ve decided to keep Guardian journalism free for all readers, regardless of where they live or what they can afford to pay. This is made possible thanks to the support we receive from readers across America in all 50 states.

... in the coming year, and the results will define the country for a generation. These are perilous times. Over the last three years, much of what the Guardian holds dear has been threatened – democracy, civility, truth.

The Guardian has been significantly impacted by the pandemic. Like many other news organisations, we are facing an unprecedented collapse in advertising revenues. We rely to an ever greater extent on our readers, both for the moral force to continue doing journalism at a time like this and for the financial strength to facilitate that reporting.

Widowed in 1893, Florence lived until 1916 at Sandford Orleigh, the Bakers’ estate in Devon, and was doubtless gratified when the Daily News called her “a refined English lady”.

The Guardian has been significantly impacted by the pandemic. Like many other news organisations, we are facing an unprecedented collapse in advertising revenues. We rely to an ever greater extent on our readers, both for the moral force to continue doing journalism at a time like this and for the financial strength to facilitate that reporting.

Jason Ward, whose popular birdwatching series Birds of North America features Christian Cooper, decides to view the injustice the same way a bird would see the world: migrating through spaces, stopping at places that benefit them and passing over ones that offer them nothing.

These are defense mechanisms that Ward and many other black nature-lovers have to employ when out in the wild – lest a situation turn sticky and they have to answer questions from a suspecting police officer. In short, in a battle of he-said-she-said, most black people know who the burden of proof falls on.

Lanham goes back to his nine rules to exemplify this. When he considers going on a specific trip, alongside weighing up the many universally good factors (nature’s beauty) as well as the bad (the possibility that he will get stung by a wasp or step on an ants’ nest), he also has to make other decisions, mostly based on his safety. “I have to make decisions about where I go, when I go, who I go with, what people will be thinking of me when I am there. I need to make sure I am wearing the right thing, that my car registration is in the right place so when I am stopped, I am not suspected of harboring something,” he says. “I have some complex equation that I have to figure out several times a fucking day.”

“I am tired of the narrative of black bodies being harmed in nature and in the outdoors,” she says. “From a practical perspective, we all pay taxes on these public lands and so to enjoy them is an exercise of our citizenship. It is what being American is all about,” she says.

“When I grew up, there was no one I knew in the natural world studying animals who looked like I did, at least not on television. And yet, still my love persisted,” he says.

In the weeks and months ahead, our journalism will investigate the prospects for a new green settlement. We will showcase the big thinkers and protagonists and amplify the arguments for authorities everywhere to consider as they lead us out of coronavirus.

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Trump caught many capitals and White House officials by surprise on 20 May, when he tweeted: “Now that our Country is ‘Transitioning back to Greatness,’ I am considering rescheduling the G-7, on the same or similar date, in Washington, DC, at the legendary Camp David. The other members are also beginning their COMEBACK. It would be a great sign to all – normalization!”

Had Abe attended the summit, he would have been required either to quarantine himself for two weeks or take a Covid-19 test on his return. Officials told Japanese media they did not want Abe to be seen to be getting privileged treatment, and cited the backlash the UK prime minister, Boris Johnson, has faced for clearing his senior adviser of breaking UK quarantine rules.

The UK is hosting a virtual coronavirus vaccine summit on 4 June intended to establish a global alliance and raise funds for research, and will hope the US decision to withdraw from the WHO does not dominate the event.

The Guardian has been significantly impacted by the pandemic. Like many other news organisations, we are facing an unprecedented collapse in advertising revenues. We rely to an ever greater extent on our readers, both for the moral force to continue doing journalism at a time like this and for the financial strength to facilitate that reporting.

In 1939, on the eve of World War II, Joseph Stalin and German dictator Adolf Hitler (1889-1945) signed the German-Soviet Nonaggression Pact. Stalin then proceeded to annex parts of Poland and Romania, as well as the Baltic states of Estonia, Latvia and Lithuania. He also launched an invasion of Finland. Then, in June 1941, Germany broke the Nazi-Soviet pact and invaded the USSR, making significant early inroads. (Stalin had ignored warnings from the Americans and the British, as well as his own intelligence agents, about a potential invasion, and the Soviets were not prepared for war.) 

Joseph Stalin did not mellow with age: He prosecuted a reign of terror, purges, executions, exiles to labor camps and persecution in the postwar USSR, suppressing all dissent and anything that smacked of foreign–especially Western–influence. He established communist governments throughout Eastern Europe, and in 1949 led the Soviets into the nuclear age by exploding an atomic bomb. In 1950, he gave North Korea’s communist leader Kim Il Sung (1912-1994) permission to invade United States-supported South Korea, an event that triggered the Korean War.

Stalin, who grew increasingly paranoid in his later years, died on March 5, 1953, at age 74, after suffering a stroke. His body was embalmed and preserved in Lenin’s mausoleum in Moscow’s Red Square until 1961, when it was removed and buried near the Kremlin walls as part of the de-Stalinization process initiated by Stalin’s successor Nikita Khrushchev (1894-1971).

4. Most of the war was spent in an 11-month siege.

5. It was the first war to feature news correspondents and battlefield photographers. 

6. The war launched Leo Tolstoy’s literary career.

7. Florence Nightingale wasn’t the war’s only famous nurse.

8. The war helped convince Russia to sell Alaska to the United States.

Unfortunately, the February Revolution also mimicked the French Revolution by giving way to anarchy, violence and repression. As Alexander Kerensky’s provisional government floundered, Petrograd’s expatriates watched in horror as the air of optimism quickly grew toxic. Their diaries and letters detail the descent into violence as looting and killing became a common occurrence.

The February Revolution had surprised the Bolsheviks as much as anyone, and they were not powerful enough to take control early in 1917, Rappaport says. The return of Bolshevik leader Vladimir Lenin from exile, however, galvanized the radical socialists. By the fall of 1917, the residents of Petrograd were so desperate for relief from the seemingly endless chaos that they cared little about who could bring it.

Rappaport says the first-hand accounts of Americans and other foreigners in Petrograd are valuable because they provide an unvarnished window into the events of 1917. “These were private citizens writing personal diary entries or letters. They didn’t have a particular political agenda. I looked at Russian accounts and had to wade through so much tedious politics. Their response, though, was natural and instinctive.”

After a secret meeting, a death sentence was passed on the imperial family, and Nicholas, his wife, his children, and several of their servants were gunned down on the night of July 16.

Between 1928 and 1940, Stalin enforced the collectivization of the agricultural sector. Rural peasants were forced to join collective farms. Those that owned land or livestock were stripped of their holdings. Hundreds of thousands of higher-income farmers, called kulaks, were rounded up and executed, their property confiscated.

Stalin eliminated all likely opposition to his leadership by terrorizing Communist Party officials and the public through his secret police.

The Soviet Union by 1948 had installed communist-leaning governments in Eastern European countries that the USSR had liberated from Nazi control during the war. The Americans and British feared the spread of communism into Western Europe and worldwide.

During the 1960s and 1970s, the Communist Party elite rapidly gained wealth and power while millions of average Soviet citizens faced starvation. The Soviet Union’s push to industrialize at any cost resulted in frequent shortages of food and consumer goods. Bread lines were common throughout the 1970s and 1980s. Soviet citizens often did not have access to basic needs, such as clothing or shoes.

At home, however, Khrushchev initiated a series of political reforms that made Soviet society less repressive. During this period, later known as de-Stalinization, Khrushchev criticized Stalin for arresting and deporting opponents, took steps to raise living conditions, freed many political prisoners, loosened artistic censorship, and closed the Gulag labor camps.

On October 4, 1957, the USSR publicly launched Sputnik 1—the first-ever artificial satellite—into low Earth orbit. The success of Sputnik made Americans fear that the U.S. was falling behind its Cold War rival in technology.

Gorbachev’s glasnost plan called for political openness. It addressed personal restrictions of the Soviet people. Glasnost eliminated remaining traces of Stalinist repression, such as the banning of books (like Boris Pasternak’s Nobel Prize-winning “Dr. Zhivago”) and the much-loathed secret police (though the KGB wouldn’t fully dissolve until the Soviet Union’s collapse in 1991). Newspapers could criticize the government, and parties other than the Communist Party could participate in elections.

The Cold War power struggle—waged on political, economic and propaganda fronts between the Eastern and Western blocs—would persist in various forms until the fall of the Soviet Union in 1991.

An unsuccessful coup by Communist Party hard-liners in August 1991 sealed the Soviet Union’s fate by diminishing Gorbachev’s power and propelling democratic forces, led by Boris Yeltsin, to the forefront of Russian politics.

Lenin advocated for Russian defeat in World War I, arguing that it would hasten the political revolution he desired. It was during this time that he wrote and published Imperialism, The Highest Stage of Capitalism (1916) in which he argued that war was the natural result of international capitalism.

When Lenin returned home to Russia in April 1917, the Russian Revolution was already beginning. Strikes over food shortages in March had forced the abdication of the inept Czar Nicholas II, ending centuries of imperial rule.

Lenin, aware of the leadership vacuum plaguing Russia, decided to seize power. He secretly organized factory workers, peasants, soldiers and sailors into Red Guards—a volunteer paramilitary force. On November 7 and 8, 1917, Red Guards captured Provisional Government buildings in a bloodless coup d’état.

The Bolshevik Revolution plunged Russia into a three-year civil war. The Red Army—backed by Lenin’s newly formed Russian Communist Party—fought the White Army, a loose coalition of monarchists, capitalists and supporters of democratic socialism.

As the economy deteriorated during the Russian Civil War, Lenin used the Cheka to silence political opposition, both from his opponents and challengers within his own political party.

After the assassination attempt, the Cheka instituted a period known as the Red Terror, a campaign of mass executions against supporters of the czarist regime, Russia’s upper classes and any socialists who weren’t loyal to Lenin’s Communist Party.

About a million people braved the cold Russian winter to stand in line for hours before paying their respects to Lenin, who was lying in state at the House of Trade Unions in Moscow.

Between 1890 and 1910, for example, the population of major Russian cities such as St. Petersburg and Moscow nearly doubled, resulting in overcrowding and destitute living conditions for a new class of Russian industrial workers.

The massacre sparked the Russian revolution of 1905, during which angry workers responded with a series of crippling strikes throughout the country.

Russia entered into World War I in August 1914 in support of the Serbs and their French and British allies. Their involvement in the war would soon prove disastrous for the Russian Empire.

Czar Nicholas left the Russian capital of Petrograd (St. Petersburg) in 1915 to take command of the Russian Army front. (The Russians had renamed the imperial city in 1914, because the name “St. Petersburg” had sounded too German.)

Russian nobles eager to end Rasputin’s influence murdered him on December 30, 1916. By then, most Russians had lost faith in the failed leadership of the czar. Government corruption was rampant, the Russian economy remained backward and Nicholas repeatedly dissolved the Duma, the toothless Russian parliament established after the 1905 revolution, when it opposed his will.

The leaders of the provisional government, including young Russian lawyer Alexander Kerensky, established a liberal program of rights such as freedom of speech, equality before the law, and the right of unions to organize and strike. They opposed violent social revolution.

The Russian Revolution paved the way for the rise of communism as an influential political belief system around the world. It set the stage for the rise of the Soviet Union as a world power that would go head-to-head with the United States during the Cold War.

The study was posted on the pre-print server MedRXiv.org, which means it wasn't peer reviewed or published in a medical journal.

During a call with reporters, the director of the CDC talked about the need to strengthen systems that monitor fo respiratory illnesses.

But later in the call, he added that the surveillance systems that were in place "really did give us eyes on this disease as it began to emerge" and that his agency was "never blind when it came to surveillance for coronavirus 19."

"The disease spread under the radar," study author Alessandro Vespignani, director of the Network Science Institute at Northeastern University in Boston, said at the time.

"When we've heard about the number of diagnosed cases, we have to be mindful that the number of people who contracted SARS-CoV-2 is actually going to be much larger than that," Holtgrave said.

Some infected people may have had no symptoms, or only mild symptoms, and so never went to the doctor. Others might have wanted to get tested but couldn't find a doctor to test them, given the shortage of tests in February and March. It was winter virus season, and so some people who actually had Covid might have been diagnosed with the flu or another illness. Still others might have been suffering Covid symptoms but didn't go to the doctor because they feared catching the virus there.

The countries had not been informed ahead of time that Trump would be announcing the possibility of holding a summit that would involve traveling even as restrictions and quarantine orders remained in place.

"The President's thinking was, there are a couple of countries that have handled the Covid crisis incredibly well, and it would be useful to have them participate in the G7 so we can learn some lessons there," he said. "Logistically to pull something like that off, I think it will take a little bit more time, so we're probably looking at the September time frame."

But questions about the size of the delegations, the logistics of travel, accommodations and security -- which is typically extremely tight at G7 summits -- were all still being weighed, according to the people familiar with the planning, along with pandemic precautions when the decision, announced Saturday, was made to delay until at least September.

Also unclear is how other G7 leaders will respond to the idea of inviting Russia, which Trump suggested Saturday, back into the group. Merkel in particular has been adamantly opposed when Trump raised the idea previously, including during a heated dinner meeting underneath the Biarritz lighthouse at last year's G7, CNN has previously reported.