The government has not yet responded to the accusations but it had previously warned people to stay away from what it called military targets.

According to the UN, air strikes conducted last week in Mekelle killed civilians including children. A senior Tigrayan figure said in a tweet that at least three bombs were dropped in the city and a hospital was among the targets in the latest strikes.

A resident has told the BBC there were air strikes in the city but they could not say what the targets were.

An ongoing communications blackout has made it difficult to get detailed, reliable information.

Meanwhile fighting on the ground has continued to intensify a week after the resumption of violence, following a five-month truce.

The UN says the renewed clashes have been displacing thousands of people in border areas in Amhara and Afar, the neighbouring regions where the fighting is concentrated.