
European Council President Charles Michel said Russia would face "further EU sanctions" following reports of alleged war crimes by Russian forces in Buca, on the outskirts of Kiev.
Michel tweeted on 3 April that he was "shocked by the horrific images of atrocities committed by the Russian army in the liberated region of Kiev".
Meanwhile, the same day human rights watch said it had "documented several cases where the Russian military has committed violations of the law of war against civilians in the occupied areas of Chernihiv, Kharkiv and the Kiev region of Ukraine".
The organization said that on March 4, Russian forces in Buca had fired firearms behind the head at least one person.
Buça's mayor, Anatoly Fedoruk, said on April 2nd that nearly 300 local residents were killed when the city was under the occupation of Russian forces. Nearly 280 are suspected of being buried in a mass cemetery, while the bodies of other victims have been left on the streets of this city.
Heavy images of this city, where bodies of residents are seen on the streets, have been distributed on social networks.
"These are the consequences of the Russian invasion," Fedoruk was quoted as saying.
Russia has yet to respond over these accusations.
Meanwhile, on 2 April, British Foreign Secretary Liz Truss said she was shocked "by atrocities in Bucha and other cities in Ukraine" and promised that the perpetrators would be prosecuted.
In his Twitter post, Michel said the European Union is helping Ukraine "gather the necessary evidence, to then send them to international courts".
The International Criminal Court has earlier opened an investigation into alleged war crimes by Russian forces in Ukraine.
Meanwhile, rapes, two cases of executions involving seven victims, and other cases of threats and violence against civilians were also documented in the Human Rights Watch report.