Witnesses and medical personnel said dozens were killed or wounded at a busy market in Togoga town on Tuesday, as ballot counting was underway across much of the rest of the country following Monday's national election.

No vote was held in Tigray because of the conflict, and the airstrike occurred as reports emerged of rebel advances in some parts of the region.

"There were lots of injured people and dead people," said 20-year-old survivor Birhan Gebrehiwet, whose house next to the market was destroyed by Tuesday's blast.

"We were stepping on them and in their blood," she added.

Birhan said she was selling drinks around lunchtime when the attack happened.

"I am sure it came from the air," she added.

An emergency worker at a hospital in the regional capital Mekele, 30 kilometres away, said six wounded people had so far been admitted -- including three young children -- adding that soldiers were preventing others from leaving Togoga.

"There are 45 injured people who are denied access, they risk death," said the emergency worker.

An ambulance driver said he was also being prevented from driving to Togoga.

"I tried to leave Mekele four times today to try and help people, but the soldiers are not letting us go," he said.

Relatives of one man who was seriously wounded and was being treated at a Mekele hospital said he had witnessed two explosions, both fired from aircraft.

- War and a peace prize -

In November, Prime Minister Abiy Ahmed sent troops into Tigray promising a swift campaign to oust its dissident ruling party.

The alliance against Tigray's renegade leadership followed peace overtures towards Eritrea made by Abiy that ended a long cold war between the neighbours and earned Abiy the Nobel Peace Prize in 2019.

In recent days, as votes were cast and counted across much of the vast nation of 110 million people, there were reports of rebel advances in Tigray.

They included the brief occupation of the town of Adigrat in the far north, and Wukro, further south nearer Mekele, residents told AFP.

Officials from Tigray's interim administration and the Ethiopian army did not immediately respond to AFP requests for comment about the attack.

The fighting in Tigray -- and its impact on civilians -- has damaged Abiy's standing as a peacemaker and reformer, but his administration has remained defiant in the face of international criticism.

Aid groups say that as a result of the fighting, 350,000 people face famine conditions in the northernmost region -- a depiction the government disputes.