South Sudan president and rebel leader agree to form unity government

The government and rebels in South Sudan have agreed to end the country's civil war and form a unity government within 60 days. But the collapse of previous peace deals means celebrations are on hold.

The truce followed a rare meeting on Tuesday between Salva Kiir, the president, and Riek Machar, the rebel leader, in the Ethiopian capital, Addis Ababa, and the threat of sanctions from east African neighbours.

Hailemariam Desalegn, the prime minister of Ethiopia, said: "They agreed fully to commit themselves to the already signed agreements and to complete all negotiations within the coming 60 days and then establish a transitional government of national unity."

Past deals to end the violence have been broken by both sides, however, plunging the world's newest country into a humanitarian crisis. Mediators from the Intergovernmental Authority on Development (Igad) – the east African bloc brokering talks – vowed to take a hard line if the rivals once again flout the agreements.

Hailemariam, the current chair of Igad, added: "Any attempt to stand in the way of peace will have consequences … If they don't abide to this agreement, Igad as an organisation will act to implement peace in South Sudan. On that, we have different options including sanctions and [other] punitive actions as well."

The US has already imposed sanctions on the head of Kiir's presidential guard and an army commander loyal to Machar. But this is the first time that South Sudan's neighbours have issued such a warning, a sign of growing frustration and concern that the unrest have repercussions for the broader region.

Thousands of people have been killed and more than 1.3 million others forced to flee their homes during the conflict in South Sudan, which gained independence from Sudan in 2011. The UN has estimated that 4 million people could be on the brink of starvation by the end of the year because violence has disrupted the planting season.

Fears that the violence could descend into genocide grew after the UN said the rebels had massacred hundreds of civilians in the town of Bentiu in April. Soon after, residents of Bor, a predominantly Dinka town, attacked members of the Nuer ethnic group camped in a UN base.

Mahboub Maalim, Igad executive secretary, said on Tuesday that Kiir and Machar should both take responsibility. "If we want to apportion blame, it's theirs," he told Agence France-Presse. "I think sometimes they thought they could win on the ground militarily, something which is very stupid."

The meeting in Addis Ababa was the first encounter between the pair since they signed a ceasefire on 9 May that was broken within hours, and only the second since the civil war began in mid-December.

Delegates for Kiir and Machar, who was vice-president until Kiir fired him, have been meeting in luxury hotels in Addis Ababa since January, with both sides squabbling over the agenda and even the venue. Previous rounds of negotiations have cost more than $17m (£10m), according to Igad.

Before the latest talks, a group of veteran African statesmen, including Joaquim Chissano, former president of Mozambique, Kenneth Kaunda, former president of Zambia, and retired archbishop Desmond Tutu of South Africa, warned in a joint letter to Kiir and Machar: "South Sudan is on the edge of a great tragedy."

The statesmen added: "Let this be your moment to follow in the footsteps of the great African leaders who have left behind a legacy of inclusive peace. Let your decisive action now to end hostilities be your legacy to all the people of South Sudan, to Africa and to the world as history will harshly judge you if you fail to do so. The fate of South Sudanese children, who have been affected by unimaginable violations, including killings, forced recruitment, rape and abductions, is in your hands."