Government officials denied attacking civilians. They blamed the international community for failing to pressure rebel groups to join the peace process, noting that several rebel leaders boycotted October's Libya talks.
"We are disappointed in the international community," said Foreign Ministry spokesman Ali Sadiq. "We still have no road map."
Humanitarian groups in Darfur, where the world is spending nearly $1 billion a year in aid and an additional $2.5 billion for peacekeepers, say the lack of progress threatens their efforts, particularly if donors turn to other world emergencies.
"Darfur is pretty high profile," said Kenro Oshidari, country director in Sudan for the World Food Program. "But it's been going on for five years. I don't think it's sustainable."
The peacekeeping mission is also at risk because its primary mandate is to enforce a peace deal that is nowhere on the horizon.
The latest complication is next year's planned national election. Rebels insist Darfur is too unstable to hold a vote, noting that more than 2.5 million people have been displaced. Since the region accounts for as much as one-fifth of Sudan's population, they say balloting should not proceed. Many groups are threatening to block election efforts by force.
"We are not going to let the census or election take place," said Tahir Elfaki, a Justice and Equality Movement official in London. "We have the means to do this. We are fighters."
Political experts said rebel groups might also be concerned that they stand to lose power in a vote, particularly since most are unprepared for a political campaign, which would require that they transform their armies into parties.
"They'd be defeated," said former Sudanese Prime Minister Sadek Mahdi, now head of the opposition Umma Party, which won the majority of Darfur votes in the last free election in 1986. "They have support for their cause, but not much political support. After an election, they wouldn't have the same prominence."
Mahdi's party has threatened to boycott the national election if Darfur doesn't participate, as some government officials have suggested. "Darfur has to be resolved before an election," he said.
Hassan Turabi, another opposition leader and head of the Popular Congress party, said impending elections might help rejuvenate peace talks, particularly if the government concludes it will be unable to exclude the restive region from voting.
