Ethiopia's Prime Minister Abiy Ahmed says government forces are now "fully in control" of the regional capital of the northern Tigray region.
The army earlier entered Mekelle as it stepped up its offensive against the Tigray People's Liberation Front.
The leader of the TPLF told Reuters it would continue to "defend our right to self-determination" and "fight these invaders to the last".
Hundreds have been killed and thousands displaced in the conflict.
It began earlier this month after Mr Abiy announced an operation against the TPLF, the regional party, accusing it of attacking the Ethiopian army's northern command HQ in Mekelle.
