The Biden administration on Thursday announced a slew of fresh sanctions and additional measures targeting Russia’s private military firm, the Wagner Group, saying it’s engaged in an “ongoing pattern of serious criminal activity” in Ukraine, the Central African Republic and Mali.

The Treasury Department identified the Wagner Group, led by Vladimir Putin crony Yevgeny Prigozhin, as a “significant transnational criminal organization.”

In the Central African Republic and Mali, the Treasury said “Wagner personnel have engaged in an ongoing pattern of serious criminal activity, including mass execution, rape, child abductions and physical abuse.” It also stands accused of destabilizing governments in Africa and targeting women, children and other civilians in Ukraine, attacking schools and hospitals, and forcibly relocating civilians, among other human rights violations.

Last week, National Security Council spokesman John Kirby told reporters at the White House that U.S. intelligence estimates indicate the Wagner Group has at least 50,000 personnel in Ukraine, most of them recruited for the fight from Russian prisons.