PRETORIA - Negotiators for the Ethiopian government and regional forces from Tigray were due to meet in the South African capital Pretoria for the first formal peace talks since war broke out two years ago.

The talks come after the Ethiopian military and their allies, who include troops from neighbouring Eritrea, captured several large towns in Tigray, a region in northern Ethiopia, over the past week.

The situation on the ground appeared to put the government in a stronger position than its opponents going into the talks, though it was under pressure from foreign powers, including the United States and European Union, to halt its offensive.

The war stems from a power struggle between the federal government and the authorities in Tigray, who dominated a coalition that governed Ethiopia for almost three decades until they lost their grip on power in 2018.

The conflict has killed thousands, displaced millions and left hundreds of thousands on the brink of famine.

It has also further destabilised the perennially volatile Horn of Africa region and complicated Ethiopia's diplomatic relations with Western allies, who have been calling for a ceasefire.

The talks, mediated by the African Union, were shrouded in secrecy. Sources from both sides gave conflicting information as to when face-to-face meetings would begin, and the African Union declined to answer questions from media.

Ethiopia's government said in a statement its delegation had left for South Africa.

"The Government of Ethiopia views the talks as an opportunity to peacefully resolve the conflict and consolidate the improvement of the situation on the ground," it said.

Kindeya Gebrehiwot, a spokesman for the Tigray forces, said the Tigrayan delegation had already arrived.

He said on Twitter that the focus of the talks would be on immediate cessation of hostilities, unfettered humanitarian access, and the withdrawal of Eritrean forces, who have fought alongside Ethiopian federal troops during the conflict.

The Tigray delegation is being led by one of its top generals, Tsadkan Gebretensae, and spokesman Getachew Reda, an official familiar with the talks told Reuters.

The delegation arrived on Sunday on a U.S. military aircraft, accompanied by Mike Hammer, the U.S. special envoy to the Horn of Africa, the official said.

Both sides had committed to the talks in South Africa earlier this month, but they were delayed for logistical reasons.

On Sunday, Pope Francis said he was following the Ethiopian conflict with trepidation.

"May the efforts of the parties for dialogue lead to a genuine path of reconciliation," he said.

(Reporting by Siyabonga Sishi in Pretoria, Wendell Roelf in Cape Town and Nairobi Newsroom, Editing by Estelle Shirbon and Angus MacSwan)