The Ethiopian government said on Tuesday that Tigrayan soldiers were surrendering in the face of an advance towards the regional capital, but the local forces reported they were resisting and had destroyed a prestigious army division.

Hundreds have died, more than 41 000 refugees have fled to Sudan, and there has been widespread destruction and uprooting of people from homes in the northern Tigray region.

The three-week war has spread to Eritrea, where the Tigrayans have fired rockets, and also affected Somalia where Ethiopia has disarmed several hundred Tigrayans in a peacekeeping force fighting al Qaeda-linked militants.

Reuters has been unable to verify statements made by either side since phone and internet connections to Tigray are down and access to the area is strictly controlled.

Prime Minister Abiy Ahmed's government said many Tigrayan combatants had responded to an ultimatum to lay down arms before a threatened offensive against Mekelle city, with half a million inhabitants. The deadline expires on Wednesday.

"Using the government's 72-hour period, a large number of Tigray militia and special forces are surrendering. Many have surrendered through the Afar region, and the remaining forces are surrendering peacefully," a government taskforce said.

'TRAGIC CONFLICT'

The battle-hardened Tigray People's Liberation Front (TPLF), which had ruled the region of more than 5-million people, gave a sharply different version, saying their troops were keeping the federal forces at bay and scoring some big victories.

Their spokesperson Getachew Reda told Tigray TV an important army unit - which he termed the 21st mechanised division - had been destroyed in an assault at Raya-Wajirat led by a former commander of that unit now fighting for the TPLF.

Billene Seyoum, the prime minister's spokesperson, told Reuters that was not true.

The United States - which regards Ethiopia as a powerful ally in a turbulent region - France and Britain were the latest foreign powers to call for peace.

Washington said it supported African Union (AU) mediation efforts "to end this tragic conflict now", while Paris and London warned against ethnic discrimination.

The UN Security Council was to hold an informal discussion later on Tuesday over Ethiopia, according to a New York-based UN source and an email seen by Reuters. South Africa, as AU chair, was to report on the conflict and de-escalation efforts.

Abiy, who won the Nobel Peace Prize last year for ending a standoff with Eritrea, has said he will not negotiate with the TPLF, though he does plan to receive AU envoys.

MYRIAD ETHNIC GROUPS

His predecessor, Prime Minister Hailemariam Desalegn, criticised international mediation efforts by "well-intentioned outsiders" in a piece for Foreign Policy magazine.

"The key problem in the international community’s approach to Ethiopia is the assumption of moral equivalence, which leads foreign governments to adopt an attitude of false balance and bothsidesism" between the federal and Tigrayan sides, he said.

Abiy, whose parents are from the larger Oromo and Amhara groups, denies any ethnic overtones to his offensive against the TPLF, saying he is pursuing criminals who have revolted against the federal government and ambushed a military base.

The TPLF says he wants to subdue Tigray to amass more personal power. Since taking office in 2018, the prime minister has removed many Tigrayans from positions in government and the security forces and arrested some on charges of corruption and human rights abuses, even though he was their former military comrade and coalition partner.

TPLF leader Debretsion Gebremichael has disputed the government version that Mekelle is encircled at a roughly 50km (31 mile) distance and told Reuters the ultimatum was a cover for government forces to regroup after defeats.

The conflict threatens to destabilise Ethiopia, a vast nation of 115-million people from myriad ethnic groups whose struggles for greater resources and power have intensified since Abiy took office.

Some school students' exams scheduled for December were postponed "due to the current situation in the country," the Education Ministry said.