Rebellious northern Ethiopian forces have accused the government of launching air strikes on the capital of Tigray region although the government denies the reports.
Tigrai TV, controlled by the northern region's Tigrayan People's Liberation Front (TPLF), said the attack on the city of Mekelle killed several civilians.
A resident of the city told Reuters one strike hit close to a market, behind a hotel.
An aid worker and a doctor in the region also said there had been an attack and a diplomat shared pictures of what they said was the aftermath, including pools of blood and smashed windows.
All asked not to be named.
Reuters could not confirm the authenticity of the images.
Ethiopia's government spokesman, Legesse Tulu, denied launching any attack.
"Why would the Ethiopian government attack its own city? Mekelle is an Ethiopian city," he said.
"Terrorists are the ones who attack cities with innocent civilians in them, not government," Legesse added.
He accused the TPLF of killing civilians in fighting in neighbouring regions.
Reuters was not able to verify any of the accounts in an area that is off-limits to journalists.
War erupted in Tigray in November between the Ethiopian military and the TPLF, the political party that controls the region, killing thousands of people and forcing more than two million to flee.
Tigrayan forces were initially beaten back but recaptured most of the region in July and pushed into the neighbouring Amhara and Afar regions, displacing hundreds of thousands more
A week ago, the Tigrayan forces said the military had launched a ground offensive to push them out of Amhara.
The military acknowledged on Thursday there was heavy fighting there but accused the Tigrayan forces of starting it.
On Monday, A Mekelle resident told Reuters one of the strikes on Monday hit close to a market behind the city's Planet Hotel about noon.
"I was a few metres away, I thought they had hit our compound," the resident said.
A doctor in the region said they heard the first attack on Monday morning. "First I heard the sounds of jet and also an explosion from afar.
"Then in the afternoon there was another sound, which seemed closer. This one seemed like it happened inside the city," the doctor said.
TPLF spokesman Getachew Reda tweeted: "#AbiyAhmed's 'Air Force' sent its bomber jet to attack civilian targets in& outside #Mekelle," referring to Ethiopia's Prime Minister Abiy Ahmed.
Diplomats are worried that renewed fighting will further destabilise Ethiopia, a country of 109 million people, and deepen hunger in Tigray and the surrounding regions.
Australian Associated Press