Two airports in Ethiopia's Amhara state which neighbours Tigray where federal troops are fighting local forces were targeted by rocket fire late on Friday, the government said, as an 11-day conflict widened. 

The airport in Gondar in Amhara state, which neighbours Tigray, was hit on Friday, while another rocket aimed at the Bahir Dar airport missed the target, the government said.

The ruling Tigray party, the Tigray People's Liberation Front (TPLF), said the Tigray Defence Forces conducted missile strikes in military bases in Bahir Dar and Gondar in retaliation for air strikes conducted by Prime Minister Abiy Ahmed's forces in various parts of the state.

Abiy sent the national defence force on an offensive against local troops in Tigray last week, after accusing them of attacking federal troops. Hundreds of people have been killed.

The prime minister has said government warplanes were bombing military targets in Tigray, including arms depots and equipment controlled by the Tigrayan forces. The government says its military operations are aimed at restoring the rule of law in the mountainous state of 5 million people.

More than 14,500 people have fled into neighbouring Sudan, with the speed of new arrivals "overwhelming the current capacity to provide aid", the UN refugee agency said on Friday.

Ethiopia's Human Rights Commission, appointed by the government but independent, said it was sending a team of investigators to the town of Mai Kadra in Tigray, where Amnesty International this week reported what it said was evidence of mass killings.

Amnesty International said on Thursday scores and possibly hundreds of civilians were stabbed and hacked to death in the region on Nov 9, citing witnesses. It said it had not been able to independently confirm who was responsible, but said the witnesses had blamed fighters loyal to Tigray's local leaders. The Tigray state government denied involvement in the reported killings.