Ethiopian security forces patrol at street after Ethiopian army took control of Hayk town of Amhara city from the rebel Tigray People's Liberation Front (TPLF) in Ethiopia on December 16, 2021. [AFP]

Tigray rebels in Ethiopia told AFP on Thursday they were in a state of "full-blown war" with the federal government, with heavy artillery attacks reported in neighbouring regions.

Tensions had been rising for months between the federal government and the authorities in the northern Tigray region, who fought a devastating civil war in 2020-2022 that killed more than 600,000 people, according to African Union estimates.

The two sides accuse each other of triggering a return to open conflict with attacks this week.

On Wednesday, the Tigray People's Liberation Front (TPLF), which dominates the region, seized control of three airports from federal police and launched attacks into the neighbouring regions of Afar and Amhara.

A humanitarian source in Afar told AFP on Thursday there were heavy artillery attacks by the rebels as they attempted to take control of the town of Yallo, near the border of Tigray.

"We are in the situation of full-blown war now," TPLF vice president Amanuel Assefa told AFP.

He confirmed fighting was ongoing in Afar and Amhara, with Tigrayan forces fighting alongside local armed groups.

The rebels already had control of Abala, on the Tigray-Afar border, on Wednesday, according to a foreign security source based in Ethiopia, while a TPLF source said they had seized several other Afar towns, though this could not be confirmed by AFP.

Regional conflict

The conflict risks turning into a regional conflagration.

Analysts say the Tigray rebels have support from Eritrea, which fears landlocked Ethiopia is planning to invade its territory to gain access to the Red Sea.

The TPLF's Assefa told AFP "we have no information about Eritrea's plan". Asked if the TPLF would ask for Eritrea to join the conflict, he said: "Not yet."

The Sudanese army is also angry with Ethiopia over its alleged support for the Rapid Support Forces that it is fighting in Sudan, and some fear it, too, could be drawn into the conflict.

'Take Addis'

Pushing into Afar and Amhara suggests the Tigrayans are planning a similar strategy to the civil war in 2020-2022 -- seeking to cut off supply lines, and ultimately threaten the capital, Addis Ababa.

"Their stated aim is to take Addis, but its tactical manoeuvres to reach the city are not yet known," said regional expert Kjetil Tronvoll, of Oslo New University College.

One of the few routes to the capital is through the Amhara town of Weldiya.

The offensive in Afar, meanwhile, is likely aimed at cutting off supplies from Djibouti, which supplies almost all of Ethiopia's international trade cargo, including fuel, Tronvoll told AFP.

Alliances

The TPLF is fighting alongside an insurgent group known as the Fano in Amhara. They forged an anti-government alliance with five other armed groups this weekend.

It shows the changing dynamics from the war of 2020-2022, when the Fano and Eritrea both fought with the government against the Tigrayans.

The government in Addis Ababa has yet to comment on the latest escalation.

The TPLF ruled the whole of Ethiopia from 1991 to 2018 before being sidelined with the rise of Prime Minister Abiy Ahmed, eventually triggering the civil war.

The Pretoria Peace Agreement ended the war and maintained an uneasy calm until late 2025, when clashes resumed. The federal government has since launched drone strikes in Tigray and massed troops at the regional border.

Rights groups have accused the TPLF of a campaign of forced recruitment this year as it prepares for renewed conflict.

The region has not recovered from the last war, with around one million people still displaced and many aspects of the peace agreement unfulfilled.