Businesses are shut in South Sudan's capital, Juba, as people celebrate the signing of a power-sharing deal aimed at ending a brutal five-year civil war.
The deal will see rebel leader Riek Machar return to government as one of five vice-presidents.
He and President Salva Kiir signed the agreement in neighbouring Sudan.
Tens of thousands of people have been killed and millions displaced in the conflict which broke out about two years after South Sudan's independence.
South Sudan seceded from Sudan in 2011 but plunged into conflict in December 2013 following a power struggle between Mr Kiir and Mr Machar.
Previous attempts to find a solution to the conflict have failed.
"An agreement on outstanding issues has been signed and this agreement expresses the commitment of all parties to a ceasefire," said Sudanese Foreign Minister Al-Dirdiri Mohamed, who helped to broker the deal.
South Sudan's ruling party has declared an unofficial holiday to celebrate the signing of the accord, reports the BBC's Nichola Mandil from Juba.
Its members are driving around neighbourhoods in Juba, using loudspeakers to spread the news, he adds.
Most businesses in the capital are shut, and people are being urged to attend a celebratory rally Mr Kiir is due to address, our reporter says.
Speaking after the signing of the accord in Sudan, Mr Kiir said the government and rebels should "rededicate ourselves to unite our people and work for a peaceful transfer of power through the ballot boxes rather than through bullets".
Mr Machar urged mediators to focus on the implementation of the deal because the "devil lies always in the implementation".
South Sudan is rich in oil, but its economy has been devastated by the conflict.
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