"We have seen the credible reports of attacks in and around Mekele. The United States condemns the continuing escalation of violence, putting civilians in harm's way," State Department spokesman Ned Price tweeted from Bogota, where US Secretary of State Antony Blinken is visiting.

"The government of Ethiopia and the Tigray People's Liberation Front must end hostilities and begin talks now," Price said.

The United States is a longstanding ally of Ethiopia but has voiced growing frustration with the military campaign launched by Prime Minister Abiy Ahmed nearly a year ago following an attack by the TPLF, the region's former ruling party, on an army camp.