US Secretary of State Antony Blinken called Saturday for the withdrawal of Eritrean and Ethiopian regional forces from the Tigray region of Ethiopia, and an end to killings and human rights violations there. His call came a day after investigations by CNN and Amnesty International into the massacre of civilians in two separate assaults in the northern Tigray region late last year.

"The United States is gravely concerned by reported atrocities and the overall deteriorating situation in the Tigray region of Ethiopia," Blinken said in a statement Saturday.

Thousands of civilians are believed to have been killed since Ethiopian Prime Minister Abiy Ahmed launched a military operation against leaders in the Tigray region. CNN has previously reported that soldiers from neighboring Eritrea have perpetrated many of the extrajudicial killings, assaults and human rights abuses in the Tigray region.