An intense flare-up of tribal clashes in southern Sudan over the last three months has killed about 900 people and could threaten upcoming elections crucial to preserving the peace deal that ended civil war with the north, AP quoted aid workers and U.N. officials as saying. If violence keeps up at the rate of the last few months, the fighting over cattle and territory is on pace to claim more lives this year than Sudan's separate ongoing conflict in the western region of Darfur. The 2005 peace agreement that ended two decades of civil war created a semi-autonomous south, established a unity government in the Sudanese capital Khartoum with representatives from the north and south and provided for sharing oil wealth. The fight over oil resources was a major trigger in the civil war and continues to threaten the peace between the former rivals. National presidential and parliament elections are scheduled for February next year _ the first national elections to include all of South Sudan in four decades. That vote and a 2011 referendum in the south on whether to secede from the north are viewed as crucial to keeping the peace. Both ballots are integral parts of the phased peace deal, and will set new parameters for powersharing. The elections will be the first test at the ballots for the southern partner, the Sudan People's Liberation Movement. But the renewed violence has raised concerns about the ability of the southern government _ heavily dependent on falling oil revenues _ to provide security in the largely underdeveloped south. Southern officials say this widespread violence could benefit their rivals in the election, who are campaigning to prove the ineffectiveness of the current government. Salva Kiir, the president of South Sudan and vice president in the national unity government in Khartoum, said the tribal fighting was «engineered» to destabilize the south and prove the ineffectiveness of the southern government. He called for a conference with traditional leaders from all the southern tribes, which started Monday, and urged them to rein in «enemies from within our ranks and without.» «There are people out there, including our own, who are crazy enough to say ... that we are not capable of governing ourselves ... cannot provide (our) own people with security,» he said at the conference. Tribal fighting is common in south Sudan. But the recent attacks are more deadly and partly fueled by the planned February 2010 elections, experts said. U.N. resident coordinator in the south, David Gressely, said that if the tribal tensions are not contained quickly, «it will be very difficult to carry out activities related to the elections.»