Ethiopian and Eritrean forces launched a “massive” joint offensive against the Tigray People’s Liberation Front (TPLF) in the northern region of Tigray on Thursday, the rebels said.

“The enemy, which has already deployed a massive military force to Eritrea, has now begun a joint campaign with the foreign invading Eritrean force to brutalize and exterminate the people of Tigray,” the rebel military command said in a statement.

AFP has been unable to independently verify the claims. Access to northern Ethiopia is severely restricted and Tigray has been under a communications lockdown for over a year.

TPLF spokesman Kindeya Gebrehiwot told AFP the attack came “from Eritrea”.

Another TPLF spokesman, Getachew Reda, said on Twitter that the rebels were “defending their positions” and reported “heavy shelling” from some locations.

Addis Ababa has not responded to requests for comment on the reported offensive.

Fighting between government forces and the rebels resumed last week after a five-month hiatus.

Clashes on the ground and airstrikes over Tigray have dashed hopes for a peaceful solution to the nearly two-year war.

Fighting had concentrated on Tigray’s southeastern border, with the rebels pushing into the neighboring regions of Amhara and Afar, forcing residents to flee.

The government on Wednesday accused the TPLF of launching a broader “invasion” into parts of western Tigray and other areas west of the initial clashes.

The rebels, in turn, claimed that the government and its neighbor Eritrea – which supported federal forces in the early stages of the war – were responsible for opening a new front.

On Thursday, the government said TPLF attacks had “continued to increase”.

“Innocent civilians are being killed; many are being evicted and property is being destroyed,” the government communications service said in a statement.

Since fighting broke out over a week ago, fighting has spread while the capital of the war-torn Tigray region has been twice hit by airstrikes.

The first airstrike on Tigray’s capital Mekele killed at least four people, including children, in a strike that UNICEF said “hit a kindergarten”.

The second, around midnight Tuesday, caused injuries and property damage, the TPLF said.

Both sides accused each other of firing first and breaking a March ceasefire that halted the worst bloodshed in northern Ethiopia.

The renewed fighting has alarmed the international community, including UN chief Antonio Guterres and senior diplomats from the European Union, Britain and the African Union (AU), who are calling for restraint.

US Secretary of State Antony Blinken on Thursday urged the Ethiopian government and the TPLF to “immediately halt military operations and redouble efforts to bring about a lasting end to the conflict.”

“We remain deeply concerned about the resumption of fighting and the lives that have been put at risk,” he said on Twitter.

Legesse Tulu, a spokesman for the Ethiopian government, responded on Twitter, saying, “The US government must end the ‘bipartisan’ rhetoric and denounce the TPLF’s destructive path that is affecting various Ethiopian communities.”

Prime Minister Abiy Ahmed, a Nobel Peace Prize laureate, dispatched troops to Tigray to overthrow the TPLF in November 2020 in response to what he described as rebel attacks on federal army camps.

For months his government denied the involvement of Eritrean forces in the conflict, although Abiy later admitted their presence in Ethiopia.

The TPLF retook most of Tigray in a surprise comeback in June 2021, expanding into Afar and Amhara before fighting reached a stalemate.

An unknown number of civilians have died and millions are suffering in a humanitarian crisis in northern Ethiopia, with the conflict hampering efforts to help those in need.

The government said on Thursday that the TPLF was diverting aid to its fighters.

US Assistant Secretary Samantha Power said humanitarian workers in Tigray, Afar and Amhara “faced unacceptable interference — including arrests, fuel looting and vehicle confiscations.”

“USAID reiterates our call for all parties to respect humanitarian operations so aid can reach those in need,” Power tweeted Wednesday.