Ethiopia and Eritrea on Sunday will head to Saudi Arabia to sign a peace agreement, a UN spokesman said Friday.

UN Secretary-General Antonio Guterres will join the leaders of the two African countries in the Saudi capital of Jeddah to attend the ceremony hosted by King Salman bin Abdulaziz.

"I believe this is a further agreement helping to cement the positive relations between them," Farhan Haq, spokesman for the Secretary-General, said in a news conference.

Haq said Guterres was going only to visit and would not be a party to the agreement between the two sides.

Both countries have begun to warm relations after decades of tension.

Eritrea seceded from Ethiopia in 1993, and from 1998 to 2000 the two countries fought a bloody war in which an estimated 70,000 people perished on both sides.

The two countries broke two decades of tension after Ethiopian Prime Minister Abiy Ahmed extended an olive branch to the Eritrean president in his inaugural speech in April.

The men met in July, vowing to revamp relations and Eritrea opened its embassy in Addis Ababa in mid-July.

Ethiopia reopened its embassy last week in the Eritrean capital of Asmara after a 20-year hiatus.