JUBA, South Sudan (AP) — South Sudan's opposition parties have rejected what was supposed to be the final version of the peace agreement with the government, threatening to destabilize an already fragile process.

On Tuesday, opposition leader and former Vice President Riek Machar and the South Sudan Opposition Alliance, the umbrella group for the splintered opposition parties, refused to initial the document in Khartoum, the capital of neighboring Sudan where the peace talks are being held, said SUNA, Sudan's state-run media.

Earlier this month South Sudan celebrated when both sides signed a power-sharing agreement and it appeared to signal an end to the country's five-year civil war, which has killed tens of thousands and displaced millions.

The opposition is contesting several outstanding issues in the most recent version of the agreement, including how many states South Sudan should have and their boundaries as well as security arrangements.

"We are ready to face the consequences," Mabior Garang de Mabior, opposition spokesman told The Associated Press.

He warned the civil war will continue and accused the government of violating the recent cease-fire, which was signed at the end of June.

There appears to be an impasse because South Sudan's government said it will not support a new proposal.

"They should sign because there's no other alternative to solve the political problems in the country without signing the peace agreement. They have to tell us what the alternative is to peace because this is what everyone's waiting to achieve," government spokesman Ateny Wek Ateny told AP.