Prime Minister Abiy Ahmed yesterday ordered Ethiopia's army to launch a final offensive against Tigray's dissident leaders in their regional capital Mekele, saying the deadline for surrender had expired.
Abiy, the winner of last year's Nobel Peace Prize, late Sunday gave the Tigray People's Liberation Front (TPLF) 72 hours to lay down their arms.
The ultimatum was rejected by the leaders of the region, whose forces have been fighting federal troops in the country's north for three weeks, displacing over 40,000 people and killing hundreds.
Ethiopia's army -- which in recent days said it was advancing on Mekele with tanks -- had been directed "to conclude the third and final phase" against the TPLF, Abiy said.
"In this final phase, great care will be given to protect innocent civilians from harm. All efforts will be made to ensure that the city of Mekele, which was built through the hard work of our people, will not be severely damaged," Abiy said.
He said "thousands" of TPLF militia and special forces had surrendered to federal forces before the deadline lapsed.
Amnesty International and other rights watchdogs warned bombarding Mekele could constitute a war crime.
It was not immediately clear how close the army was to the city. A communications blackout in Tigray and restrictions on reporting have made verifying claims from both sides difficult.
Diplomats briefed on the fighting told AFP Wednesday that federal forces were at least 30 kilometres (18 miles) from Mekele to the north and the south.
The threatened assault and fears for Mekele's half a million inhabitants accelerated diplomatic efforts this week to mediate, with the UN Security Council holding its first meeting on the crisis on Tuesday.
UN Secretary General Antonio Guterres urged "the leaders of Ethiopia to do everything possible to protect civilians" as the US, EU and other international powers encouraged mediation through the African Union, headquartered in Addis Ababa. Abiy stressed that Ethiopia's defence forces had "carefully devised" a strategy to defeat the TPLF in Mekele without harming civilians or public property. "We call on the people of Mekele and its environs to disarm, stay at home and stay away from military targets" and assist by handing over TPLF elements in their midst, Abiy said.