Mr. Putin said in a phone call Tuesday with the German chancellor, Angela Merkel, that Ukraine was on the brink of civil war, a point Mr. Medvedev also made at a news conference later in Moscow, adding that the government in Kiev was to blame. Mr. Medvedev also repeated the Kremlin’s frequent assertion that Russian speakers were under threat in Ukraine — the very claim United Nations officials rejected in their report.“The only way to preserve Ukraine and calm the situation,” Mr. Medvedev said, requires “recognizing that Russian citizens are the same as Ukrainians and, therefore, can use their own language in everyday life.”