UK PM calls Russian attacks on civilians 'war crimes'

British Prime Minister Boris Johnson on Sunday said Russian troops were guilty of war crimes in Ukraine after Kyiv retook control of areas around the capital and discovered mass graves and apparently executed civilians.

"Russia's despicable attacks against innocent civilians in Irpin and Bucha are yet more evidence that Putin and his army are committing war crimes in Ukraine," he said.

"No denial or disinformation from the Kremlin can hide what we all know to be the truth - Putin is desperate, his invasion is failing, and Ukraine's resolve has never been stronger."

Johnson added that the UK was supporting the International Criminal Court's investigation into atrocities committed in Ukraine.

"The Justice Secretary has authorised additional financial support and the deployment of specialist investigators - we will not rest until justice is served," he added.