The Ethiopian military has seized control of the town of Wikro, 50 kilometers (30 miles) north of the Tigrayan capital, a senior official said on Friday, a day after the government said it was beginning the "final phase" of an offensive in the northern region.

Federal forces have captured Wikro "and will control Mekelle in a few days," Lieutenant-General Hassan Ibrahim said in a statement. Government troops had also taken control of several other towns, he said.

On November 21, the government gave the Tigray People's Liberation Front (TPLF) until November 25 to lay down arms or face an assault on Mekelle, a city of 500,000 people, raising fears of extensive civilian casualties.

Prime Minister Abiy Ahmed accuses Tigrayan leaders of starting the war by attacking federal troops at a base in Tigray on November 4. The TPLF says the attack was a pre-emptive strike.

A commitment to protecting civilians, but no talks with TPLF

Abiy, who announced on Thursday that the military was beginning the "final phase" of its offensive, received African peace envoys at his office in Addis Abbas on Friday, saying that he will continue military operations in the restive Tigray region and his government will protect civilians in Tigray.

The statement issued after Abiy met the African Union envoys - former presidents Ellen Johnson-Sirleaf of Liberia, Joaquim Chissano of Mozambique and Kgalema Motlanthe of South Africa - said the government was committed to the "protection and security of civilians", but didn't mention any plans for further discussions with them or any talks with the TPLF to end fighting.

The envoys had been sent to Addis Ababa to help mediate in the conflict, something that Abiy had already made clear he did not want.

The prime minister, who won last year's Nobel Peace Prize for ending a two-decade standoff with Eritrea, has said he will not talk to TPLF leaders until they are defeated or give up.

Humanitarian concern

Thousands of people are already believed to have been killed following air strikes and ground fighting. The United Nations estimates 1.1 million Ethiopians will need aid as a result of the conflict.

The bloodshed has sent shockwaves through the Horn of Africa. More than 43,000 refugees have fled to Sudan. TPLF rockets have hit the capital of neighboring Eritrea.

UN Secretary-General Antonio Guterres stresses the need to ensure the protection of civilians, human rights and aid access and "appreciates the statement by Prime Minister Abiy today reaffirming the Federal Government's utmost commitment to these obligations," UN spokesman Farhan Haq said on Friday.

Pope Francis renewed a call for an end to the conflict on Friday and for political dialogue to resolve it. A Vatican statement said the pope was praying for the country and appealed to both sides for the protection of civilians.

(With input from agencies)