European Union top diplomat Kaja Kallas and several of the bloc's foreign ministers have taken part in events to commemorate Russia's massacre in the Ukrainian town of Bucha four years ago.

"Bucha has come to symbolize the cruelty of Russia’s war," 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.

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

"Of the civilians killed, many were shot at close range. Some with their hands tied behind their backs," Kallas said.

"Four years after these mass killings, we remember the victims. What happened here cannot be denied."

Since the atrocities in Bucha were discovered, European countries have been considering establishing a tribunal for Russia's war crimes. Kallas said the EU is committed to holding Russia accountable.

"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 accompanied EU ministers.

"We are pushing forward with the special tribunal, the register of damages, and the claims commission to ensure no crime goes unpunished," Sybiha said.

Ukraine has been working with the Council of Europe, an international human rights body based in the French city of Strasbourg and independent of the EU, to set up a special tribunal for Russian war crimes.

Under the plans, the tribunal is to be based in The Hague and is intended to hold senior figures in the Russian leadership accountable. EU countries can decide whether they want to participate in the tribunal.

Tuesday's delegation also included German Foreign Minister Johann Wadephul and his Polish and Italian counterparts, Radosław Sikorski and Antonio Tajani and well as several other EU representatives.

The commemorations in Bucha are to be followed by consultations of EU foreign ministers focused on "the battlefield situation, energy security, and Ukraine’s path to the EU," Sybiha said.