Ethiopian forces on Friday carried out an air strike on Tigray's capital Mekele, a rebel spokesman said.
Kindeya Gebrehiwot, a spokesman for the Tigray People's Liberation Front, told AFP that “a civilian residential area and a kindergarten” were hit in Mekele.
Two humanitarian sources said they had been informed of an air strike in Mekele but no other details were available.
Tigrai Television showed images of damaged buildings and what appeared to be wounded people lying on the ground being attended by medical personnel.
An aid organisation confirmed its staff in Mekele heard an explosion and anti- aircraft gunfire.
Earlier on Friday the Ethiopian government issued a statement urging Tigrayan citizens into stay away from military and training facilities, saying it intended to “take actions to target the military forces”.
“While the readiness of the federal government to talk unconditionally is preserved, it will take action targeting the military forces that are the source of the anti-peace sentiment of the TPLF (Tigray People's Liberation Front),” the Government Communication Service said in a statement.
Heavy fighting broke out in Tigray on Wednesday, disrupting a five-month ceasefire.
The Tigray People's Liberation Front and the central government blamed each other for the escalation after negotiations to end the conflict, which has raged for almost two years, made little progress.