Ukraine and Russia: What you need to know right now

WAR CRIMES PROBE * Ukraine said 50 of some 300 bodies found in Bucha northwest of the capital, Kyiv, were victims of extra-judicial killings by Russian troops. * Russia said alleged "crimes" by its troops in Bucha were a "provocation" and no resident suffered. * Rights group Human Rights Watch said it had documented "apparent war crimes" by Russian forces.

Ukrainian authorities were investigating possible war crimes by Russia after finding hundreds of bodies, some bound and shot at close range, strewn around towns near Kyiv after Kremlin forces withdrew to refocus attacks elsewhere. WAR CRIMES PROBE

* Ukraine said 50 of some 300 bodies found in Bucha northwest of the capital, Kyiv, were victims of extra-judicial killings by Russian troops. Reuters could not verify the report. * Satellite images showed a 45-foot (14-m) -long trench dug into the grounds of a church where a mass grave was found.

* Ukraine called for an International Criminal Court investigation that France and Britain said they would support. * Russia said alleged "crimes" by its troops in Bucha were a "provocation" and no resident suffered.

* Rights group Human Rights Watch said it had documented "apparent war crimes" by Russian forces. FIGHTING

* Ukraine's General Staff said Russia was expected to mobilize about 60,000 reservists. Reuters could not independently confirm the claim. * Explosions were heard early on Monday in the cities of Kherson and Odesa, in the south, while air raid sirens sounded across the east.

* Heavy fighting has continued in Mariupol as Russian forces attempt to take the southeastern port city, British military intelligence said. ECONOMY

* Ukraine demanded crippling new sanctions on Russia from major Western powers over what it called a "massacre" in Bucha. * Germany said the West would agree to impose more sanctions on Russia in the coming days, with its defense minister saying the European Union should discuss ending imports of Russian gas.

* French President Emmanuel Macron said a new round was needed and that there were "very clear clues pointing to war crimes" by Russian forces in Bucha. PEACE TALKS

* Ukrainian President Volodymyr Zelensky appeared in a video aired at the Grammy Awards and appealed to viewers to support Ukrainians "in any way you can". * Russia said it had requested a U.N. Security Council meeting because of what Moscow called Kyiv's attempts to disrupt peace talks and escalate violence with a "provocation" in Bucha.

QUOTES * "What is more opposite to music? The silence of ruined cities and killed people," Zelensky said in his Grammy video appearance.

* "I recognized him by his sneakers, his trousers. He looked mutilated, his body was cold," said Tetyana Volodymyrivna, a resident of Bucha, describing her husband.