European Union top diplomat Kaja Kallas has arrived in Kiev to take part in events to commemorate Russia's massacre in the Ukrainian town of Bucha four years ago.

"Each visit is a powerful reminder of Ukraine’s courage and resilience," Kallas said on Tuesday.

When Bucha, located to the west of the Ukrainian capital, was recaptured by Ukrainian forces in March 2022, weeks after if was occupied by Russia, hundreds of dead civilians were recovered.

"We will do everything we can to ensure full accountability for Russia’s crimes," Kallas said.

Since the atrocities in Bucha were discovered, European countries have been mulling to set up a tribunal for Russia's war crimes.

"Comprehensive accountability for Russian crimes is vital to restore justice in Europe. And today, we will advance accountability efforts," said Ukrainian Foreign Minister Andrii Sybiha, who welcomed Kallas in Kiev.

Russian officials continue to reject the accusations and claim that the atrocities in Bucha were staged.