KHARTOUM - A north-south peace deal in Sudan is in danger of unravelling, threatening a return to full scale civil war even as world leaders press for an end to violence in the western region of Darfur.

The two-decade north-south conflict, Africa's longest, left around 2 million people dead.

Fighting ended after a 2005 peace deal between the dominant northern National Congress Party (NCP) and the former southern rebels, the Sudan People's Liberation Movement (SPLM), but the SPLM says implementation has stalled and tensions are rising.

On Tuesday, Sudanese security forces raided the offices of the SPLM in Khartoum, just a day after SPLM leader and president of the government of south Sudan, Salva Kiir, warned that the country was in danger of reverting to north-south war.

"It's the most blatant move that I can think of offensive action by the NCP against the SPLM," David Mozersky, of the International Crisis Group (ICG), said of the raids.

"I think it's very worrying," he said.

A standoff between SPLM troops and the northern army in South Kordofan in central Sudan last week almost led to an armed confrontation.

"You are entering a very risky period," said Patrick Smith, editor of the London-based Africa Confidential.

Mozersky said the parties could use some outside help in the form of "a more robust international response" in settling differences. "It (the partnership) is probably one of the most important elements of a successful implementation," he said.

But the international community has focused almost all its attention on Darfur, where international experts say a four and a half year conflict has claimed some 200,000 lives and driven 2.5 million from their homes, figures Khartoum disputes.

"The north-south deal is being sacrificed on the altar of the Darfur deal," Smith told Reuters.


"REARMING"

The SPLM has consistently raised doubts about the sincerity of the NCP, saying it has been implementing the Comprehensive Peace Agreement (CPA) selectively and has tried to renegotiate some aspects of the text.

The most contentious issues include the protocol on the oil-rich Abyei area, demarcation of the north-south border and withdrawal of northern forces from the south.

SPLM officials also accuse the NCP of withholding funds for a census crucial for elections in 2009 and a referendum on the secession of the south in 2011.

On Monday, Kiir said the peace deal was at risk.

"I am alarmed, worried and deeply concerned about the status of CPA implementation," he told the parliament in Juba, capital of south Sudan.

"I am worried Mr. Speaker that it is likely that Sudan will revert again to war if we do not act now with our partner NCP."

An NCP spokesman declined immediate comment on the latest developments. The NCP has previously denied SPLM allegations it is stalling on the deal and said implementation is going well.

SPLM officials have issued similar warnings in the past, but the ICG's Mozersky said, "it seems to be coming up with increasing regularity".

Smith said the statement was Kiir's "strongest criticism ever" of the pace of implementation of the peace deal and that both sides seem to be gearing up for the worst.

"The reality there is that both sides have been rearming over the past two years, which indicates that they do not have much faith in peace process," he said.

Could the country slip back into a north-south war as Kiir suggests? "I don't think one can rule that out," Smith said.