What you need to know:
- The conflict resumed last week after a five-month lull, with clashes on the ground and air raids over Tigray dashing hopes of peacefully resolving the nearly two-year war.
- Fighting had been concentrated around the southeastern border of Tigray, with the rebels pushing into the neighbouring Amhara and Afar regions, sending residents fleeing.
Fighting in northern Ethiopia between government forces and Tigrayan rebels erupted along a new front on Wednesday, the warring sides said, as the Tigray region was hit by another air strike.
The conflict resumed last week after a five-month lull, with clashes on the ground and air raids over Tigray dashing hopes of peacefully resolving the nearly two-year war.
Fighting had been concentrated around the southeastern border of Tigray, with the rebels pushing into the neighbouring Amhara and Afar regions, sending residents fleeing.
But Prime Minister Abiy Ahmed's government on Wednesday accused the Tigray People's Liberation Front (TPLF) of launching "an invasion in the direction of Wag, Wolqait and our border areas with Sudan (Amhara region)", west of the site of the most recent clashes.
"Our heroic national defense forces are defending this invasion with full preparedness and resolve," the government communications service said in a statement.
TPLF spokesman Getachew Reda in turn alleged that the government and its neighbour Eritrea -- which backed federal forces during the war's early phase -- were responsible for opening a new front.
"The Abiy regime, along with the Asmara regime, did launch (an) offensive in these fronts. We are defending our positions," he said in a message to AFP.
Wolqait, also spelt Wolkait, lies in western Tigray, a disputed region claimed by Tigrayans and Amharas and currently occupied by Amhara forces.
The TPLF has repeatedly said the region is a "non-negotiable" part of Tigray.
Access to northern Ethiopia is severely restricted and it is not possible to independently verify the situation on the ground or the claims by the warring sides.
Reports of a fresh offensive came as Tigray's capital Mekele was hit by a second air strike since Friday.
The bombing occurred "close to midnight" on Tuesday near Mekele general hospital, said Kibrom Gebreselassie, chief clinical director at the city's Ayder Referral Hospital.
"Casualties are arriving to Ayder Hospital," he said on Twitter, without giving details.
"Night time drone attack in Mekele. No conceivable military targets!" Getachew said on Twitter. "Mekele Hospital among the targets and at least three bombs dropped."
The TPLF later said the strike caused civilian injuries and property damage. A humanitarian source confirmed the strike but did not elaborate further.
Government officials did not comment on the bombing. The resumption of fighting has sparked international concern, with calls for restraint and the protection of civilians.
The UN children's agency UNICEF condemned a separate air strike on Mekele on Friday -- the first in many months -- that "hit a kindergarten" and killed at least four people, including children.
TPLF-linked channel Tigrai TV had put the death toll at seven, including three children.
But Addis Ababa said it was only targeting military sites and accused the TPLF of "dumping fake body bags in civilian areas" to manufacture outrage.
Residents, diplomatic and humanitarian sources have said that in recent days TPLF fighters have pushed about 50 kilometres (30 miles) south from Tigray into Amhara and to the southeast into Afar.
On Tuesday, Getachew told a press conference "we have defended our positions and we are now launching a counter-offensive".
"Abiy keeps making miscalculation after miscalculation, he keeps sending reinforcements and we'll continue to neutralise (them) and that will take us probably deeper and deeper into Amhara region."
Abiy's government announced on Saturday that federal forces had pulled back from the Amhara town of Kobo, lying about 15 kilometres south of Tigray, to avoid "mass casualties".
A local NGO in Afar, the APDA, said on Twitter about 18,000 people had been displaced and roads in one area were "clogged with fleeing people".
Abiy, a Nobel Peace laureate, sent troops into Tigray to topple the TPLF in November 2020 in response to what he said were rebel attacks on federal army camps.
The TPLF mounted a comeback, recapturing most of Tigray in June 2021 and expanding into Afar and Amhara, before the fighting reached a stalemate.
Unknown numbers of civilians have died and millions need humanitarian aid. Since the latest fighting flared, the international community has issued appeals for restraint, including from UN chief Antonio Guterres and the African Union (AU).
The two sides have been at odds over who should lead negotiations -- Abiy's government says the AU should broker dialogue while the TPLF has favoured Kenya's outgoing president Uhuru Kenyatta.
The March truce allowed the resumption of international aid convoys to Tigray after a three-month break, but the stricken region still faces severe food shortages.