Ethiopian Prime Minister Abiy Ahmed says he is launching the “final phase” of the army’s operation in the northern region of Tigray after weeks of fighting.
He said the military would try not to harm civilians in the regional capital Mekelle – a city of 500,000 people – and urged residents to stay at home.
The TPLF party, which controls Mekelle, has vowed to keep fighting.
The UN warns of possible war crimes if the Ethiopian army attacks Mekelle.
Mr Abiy’s announcement comes after a deadline he gave for Tigray fighters to surrender passed on Wednesday.