The Ethiopian government has said that major cities in the Amhara region had been "freed" after days of fighting between army troops and militia fighters.
There has been no official toll from the unrest, but hospital doctors in two of the affected cities told AFP that many civilians had been killed or injured.
Prime Minister Abiy Ahmed's government last week declared a six-month state of emergency in Amhara after the clashes erupted, just nine months after the end of a devastating two-year war in the neighbouring Tigray region.
"These cities have been freed from the threat of these bandits," a statement by a federal government emergency body said on Wednesday, listing six towns including the regional capital Bahir Dar and the holy city of Lalibela, a UNESCO World Heritage site.
The State of Emergency General Directorate said security forces were "clearing" members of the "defeated extremist group" from hideouts including heritage and religious sites.
It also announced curfews in the six cities – Bahir Dar, Lalibela, Gondar, Shewa Robit, Debre Berhan and Debre Markos – until August 23, and said 14 people had been arrested in the national capital Addis Ababa.
Access to Amhara is restricted for journalists and it is not possible to independently verify the situation on the ground.
Although the Amhara militias fought alongside federal troops in the Tigray conflict, tensions emerged earlier this year after the government announced it was dismantling regional forces across Ethiopia.
The move triggered protests by Amhara nationalists who said it would weaken their region.
Last November's Tigray peace deal was also not welcomed by many in the Amhara community, the second largest ethnic group in Ethiopia, and once its economic and political elite.
US expresses concern
The United States has expressed concern about the new front in Africa's second most populous country, and several Western nations advised their citizens against travelling to Amhara.
The regional administration had said late Tuesday that "relative peace and stability" was being restored, although some residents reported continuing gunfire Wednesday.
Ethiopian Airlines also announced it was resuming flights to Bahir Dar and Gondar from Thursday after suspending operations on Tuesday.
Local residents told AFP earlier that federal troops were pushing back Fano militia fighters in Gondar and Lalibela, which is renowned for its ancient rock-hewn churches.
"Things seem to be changing today," said Simachew, a Gondar rickshaw driver.
The Ethiopian army, backed by tanks and armoured vehicles, "is taking control of most parts of the city after heavy fighting for the past couple of days".
A Lalibela resident who gave his name only as Ayalew said federal troops were stationed on the airport road, adding: "Fano has left the city and are in the forest."
'Running out of medicine'
A doctor at Gondar University Hospital told AFP about 20 people had died after reaching the facility and more than 190 were injured, mostly civilians.
"We are also running out of food and medicine," the doctor added on condition of anonymity. "In this facility, patients are dying due to a lack of oxygen and blood."
In Bahir Dar, a doctor at Felege Hiwot hospital said they had received 130 injured civilians and that 10 people had died.
"People are coming here by foot with their families carrying them on their shoulders, taking their own risks on the roads," the doctor said.
"Ambulances have stopped due to the heavy risk in the city."
Children’s lives at risk
UK charity Save the Children warned on Wednesday that "children's lives hang in the balance" in Amhara and called on the warring parties to allow access for humanitarian aid.
Under the terms of the curfews announced on Wednesday, the movement of all vehicles, except emergency and security vehicles, is forbidden after 7pm and public meetings or rallies have been banned.
The directorate did not give any information about those arrested in the capital.
On Sunday, journalist Bekal Alamirew was arrested at his home and remains in detention in Addis Ababa, a relative told AFP.
It was the fourth time Bekal, founder and chief editor of YouTube news channel Alpha TV, has been arrested since the war in Tigray was unleashed in November 2020, the family member said, requesting anonymity.
However, it was not known if his arrest was connected to the Amhara violence.