The Ethiopian government and regional forces from Tigray have agreed to cease hostilities in a dramatic diplomatic breakthrough two years into a war that has killed thousands, displaced millions and left hundreds of thousands facing famine.
Just over a week after formal peace talks mediated by the African Union (AU) began in the South African capital Pretoria, delegates from both sides signed an agreement described by an AU official as a "permanent cessation of hostilities".
"The two parties in the Ethiopian conflict have formally agreed to the cessation of hostilities as well as to systematic, orderly, smooth and co-ordinated disarmament," Olusegun Obasanjo, head of the AU mediation team, said at a ceremony.
Obasanjo, a former Nigerian president, said the agreement also included "restoration of law and order, restoration of services, unhindered access to humanitarian supplies, protection of civilians".
An agreement had not been expected so soon.
Earlier on Wednesday, the AU had invited media to what it described as a briefing by Obasanjo.
It was only when the event began, about three hours behind schedule, that it became clear a truce was about to be signed.
"This moment is not the end of the peace process. Implementation of the peace agreement signed today is critical for its success," Obasanjo said, adding that this would be supervised and monitored by a high-level AU panel.
He praised the process as an African solution to an African problem.
Ethiopian government representative Redwan Hussein, who is Prime Minister Abiy Ahmed's National Security Adviser, said all parties should be true to the letter and spirit of the agreement.
In response, Tigray delegate Getachew Reda, a spokesman for the regional authorities, spoke of the wide scale death and destruction in the region and said it was his hope and expectation that both parties would honour their commitments.
United Nations Secretary-General Antonio Guterres welcomed the truce, according to UN spokesman Stephane Dujarric.
"It is very much a welcome first step, which we hope can start to bring some solace to the millions of Ethiopian civilians that have really suffered during this conflict," Dujarric told reporters.
Troops from Eritrea, a separate country which borders Tigray, as well as forces from other Ethiopian regions, have taken part in the conflict on the side of the Ethiopian army.
Neither Eritrea nor the regional forces participated in the talks in South Africa and there was no mention at Wednesday's ceremony of whether they would abide by the truce.
The war stems from a catastrophic breakdown in relations between the Tigray People's Liberation Front (TPLF), a guerrilla movement turned political party which dominated Ethiopia for 27 years, and Abiy, who was once part of their ruling coalition but whose appointment in 2018 ended the TPLF's dominance.
Escalating tensions in 2018-20, including over Abiy's peace deal with the TPLF's sworn enemy Eritrea, and the TPLF's decision to defy him by holding regional elections in Tigray that he had postponed in the rest of Ethiopia, tipped the feuding parties into war.
Wednesday's agreement does not address the deeper political tensions that contributed to the conflict.
The AU said in a statement it stood ready to continue accompanying the Ethiopian peace process "towards a more democratic, just and inclusive Ethiopia in which youth, women and men participate fully and in peace".
The TPLF has accused Abiy of centralising power at the expense of the regions and oppressing Tigrayans, which he denies, while Abiy has accused the TPLF of seeking to return to power at the federal level, which it rejects.
The UN says the war has led to a de facto blockade of Tigray that has lasted almost two years, with humanitarian supplies of food and medicines unable to get through most of the time.
Some aid supplies did get delivered to Tigray between March and August this year during a temporary ceasefire which broke down in August, but the World Health Organisation said last week Tigray had run out of vaccines, antibiotics and insulin.