The capital of Ethiopia’s northern Tigray region has come under heavy shelling from government forces, aid workers and regional officials say.
The centre of Mekelle is being hit “with heavy weaponry and artillery,” the ruling regional party said.
The Ethiopian army has been locked in conflict with the Tigray People’s Liberation Front (TPLF) for weeks.
It says it hopes to seize the city from the TPLF within days but will avoid harming its 500,000 civilians.
Hundreds of people have reportedly been killed, and thousands have been forced from their homes as Ethiopian forces have seized towns.
The Ethiopian military earlier said it had captured the town of Wikro, north of Mekelle, along with several other towns in the region.
Details of the fighting are hard to confirm because all phone, mobile, and internet communications with the Tigray region have been cut.
TPLF leader Debretsion Gebremichael told Reuters in a text message that Mekelle was under “heavy bombardment”, and said that government forces had started an operation to capture it.
A separate TPLF statement, reported by AFP, urged “the international community to condemn the artillery and warplane attacks and massacres being committed”.
It also accused the Eritrean government of involvement in the attack on Mekelle.
Aid agencies and diplomats have been told by residents there have been explosions in the north of the city.
The Ethiopian government has not commented on the latest development. It said on Friday it had advanced to within 12 miles (20km) of the city and was beginning the “final phase” of an offensive.
A spokeswoman for Prime Minister Abiy Ahmed said Ethiopian forces would not “bombard” civilian areas.
“The safety of Ethiopians in Mekelle and Tigray region continues as a priority for the federal government,” Billene Seyoum added.