US President Joe Biden said major war crimes were being uncovered in Ukraine as Russian forces withdrew from Kiev and its environs. He said the brutal scenes of cold-blooded executions were the reason for the escalation of the new sanctions of the United States against Moscow.

“Responsible countries must unite and punish those responsible,” Biden said in a statement to the media from Washington. “We will continue to increase economic costs and pain for Putin, and we will continue to isolate Russia even more,” he added.

The new sanctions are aimed at increasing the burden on the Russian economy, which has been brought to its knees by Western sanctions. So far, however, this has not deterred Putin in his attempt to subjugate Ukraine.