South Sudan warring parties sign 'final' peace deal

South Sudan's warring parties on Wednesday signed what they say is the final peace agreement to end the country's five-year civil war, which has killed tens of thousands and displaced millions.

Several preliminary agreements have already been signed but both sides say this is the concluding version.

President Salva Kiir and head of the opposition, Riek Machar as well as the other opposition parties signed the "final final" deal in neighboring Ethiopia, government spokesman Ateny Wek Ateny said. He said the agreement is acceptable to all parties and noted that Kiir and Machar had an amicable chat after the signing.

"The president was interacting very well with Riek Machar ... he was talking to him in a very friendly way," said Ateny.

The latest signing comes following weeks of negotiations in Khartoum, Sudan, on outstanding issues between the factions. While the government is optimistic about the new deal, many international observers remain skeptical.

"We remain concerned about the parties' level of commitment to this agreement and to the Cessation of Hostilities Agreement," said a statement on Wednesday by the UK, the US and Norway, the troika that worked to bring South Sudan to independence in 2011.

To be convinced of both sides' commitment to peace, they need to see a significant change in approach, said the three countries in a statement, indicating they want to see an end to the violence, full humanitarian access given to aid workers, the release of political prisoners and checks on executive and majority power, as well as the transparent use of resources.

A Washington-based advocacy group also questioned the deal.

"Today's peace deal lacks meaningful checks and balances on a presidency that already wields immense powers, which are primarily used to loot the country's resources and deploy extreme violence against opponents," said John Prendergast, founding director of the Enough Project, which has focused on South Sudan.