Rebel forces fighting in northern Ethiopia have agreed to a government offer of a truce to allow aid deliveries to reach millions of people in urgent need of assistance.

No aid has been delivered to the Tigray region since mid-December, with the government accused of imposing a blockade. It blames rebel forces.

The TPLF rebels said they would respect the ceasefire as long as aid deliveries resume "within reasonable time".

The 16-month war has killed thousands.

More than two million people have been forced to flee their homes.

The head of the World Health Organization (WHO) Tedros Adhanom Ghebreyesus, who is from Tigray, has described the situation there as "catastrophic".

In January, the World Food Programme said that almost 40% of Tigrayans were suffering from what it called "an extreme lack of food". It also found that half of all pregnant and breastfeeding women were malnourished.

Some nine million people need aid in Tigray and neighbouring regions, which have also been affected by the fighting.

Tigray has also been hit by a communications blackout with the internet and phone services cut.

An unknown number of people have died from hunger or the lack of medical supplies. Conditions have been so bad, even doctors have been forced to beg for food.

The United Nations says at least 100 humanitarian lorries are needed to transport aid every day to the region.

The US, UN and European Union have all welcomed the truce, which follows a visit to Ethiopia by US Special Envoy to the Horn of Africa David Satterfield.

In its statement on Thursday, the government said that the truce was "indefinite" and "effective immediately", but added that it would only improve the lives of people in the north of the country if the move was reciprocated.

It called on the Tigrayan forces to "stop further aggression and withdraw from areas they have occupied in neighbouring regions".

In response, the Tigray People's Liberation Front (TPLF) said it "will do everything it can do to make sure this cessation of hostilities is a success".

Fighting broke out in November 2020 following months of tension between the federal authorities and the TPLF, which governed Tigray, Ethiopia's northernmost region.

Within weeks, Prime Minister Abiy Ahmed said the conflict was over when federal forces took the regional capital Mekelle. But the TPLF later fought back and regained control of much of Tigray.

When the rebels retook Mekelle last June, Mr Abiy declared a unilateral ceasefire. But the TPLF said it would not observe this unless it was recognised as the legitimate authority in Tigray.