The President of Ukraine has accused Russian troops of genocide. Volodymyr Zelenskyy visited a suburb of the capital on Monday to "show the world" mass graves and other atrocities.

Ukrainian troops have pushed back Russian forces around Kyiv. On Saturday, they retook the town of Bucha, about 40 kilometers to the northwest. They say they found the bodies of more than 400 civilians.

The Ukrainians say some people had their hands and feet tied then were shot at close range. They accused the Russians of strangling, raping and torturing people, including children.

Zelenskyy said the Russians are guilty of war crimes. He said what he has seen will make it "very difficult to negotiate."

Russian leaders refuted the allegations. Foreign Minister Sergey Lavrov said all troops left the town last week. He said Ukrainians and their "Western patrons" staged the graves and corpses to "undermine Russia."

United Nations officials have confirmed that more than 1400 civilians have been killed throughout Ukraine. They admit the actual number could be much higher.