After years of genocidal attacks, many thought the situation in the Darfur region of Sudan could not get worse. But a raid on African Union (AU) peacekeepers was proof that things could indeed deteriorate further. The bold attack threatens to derail international efforts to bring peace to the shattered region and unleash yet more violence.

Failure to identify the culprits and make them pay for their actions could fatally undermine any hope for some settlement of the ongoing conflict. Peace was always a long shot, but this brazen assault lengthened the odds still further.

Inhabitants of Darfur are primarily African Christians and animists, who have long complained of discrimination by the Sudanese government, which is dominated by Arabs and Muslims. A rebel movement coalesced in early 2003 to assert the rights of southern Sudanese. After several attacks on government facilities and garrisons, war was launched with a ferocious counter attack. The United Nations reckons that four years of fighting in Darfur have cost at least 200,000 lives and left another 2.5 million people homeless.

In crude terms, the violence has pitted government-backed Arab tribes against non-Arabs — or more precisely, Arabs have slaughtered non-Arabs. A little after a year of fighting, a ceasefire was brokered, and a 7,000-person Afrian Union peacekeeping contingent was deployed to western Sudan. The ceasefire existed more in name than reality as a militia known as the janjaweed, reportedly armed and supported by the government — an accusation that is denied by Sudanese officials — was unleashed against civilians in Darfur, killing thousands and creating a humanitarian crisis of vast proportions.

Hopes were raised by the May 2006 peace agreement between the Sudanese government and the rebels. But only one of the rebel groups signed the deal, the janjaweed continued their assaults, and peace has proven illusory. Late last month, an AU peacekeeping base was overrun: as many as 20 soldiers were killed and wounded, dozens more were kidnapped and supplies stolen.

The attack was the boldest yet against the peacekeepers since they were deployed in Darfur. It is still unclear who was responsible for the attack, but it has two especially troubling implications for the conflict in Darfur. First, if, as suspected, the raid was carried out by one of the rebel groups, then it signals a dangerous evolution in the situation. A rebellion against the government has become a bloody free-for-all among armed groups. Indeed, there have been reports of more than a dozen attacks on aid workers in recent weeks, prompting a withdrawal by many humanitarian groups.

Second, and even more troubling, the raid exposed the inadequacies of the AU peacekeepers. The current force is supposed to expand from 7,000 to 26,000 this year. The expanded contingent will be under a joint AU-United Nations command, but the Sudanese, with AU backing, are demanding that it be an all-African force. But it is unclear whether there are sufficient troops with the skills and the equipment needed to serve as peacekeepers. The base that was overrun was staffed by Nigerian forces, reputed to be the best equipped and most experienced among African peacekeepers.

While Nigeria has said that it will not be deterred by the attack, other nations are not so sure. Senegal's president, Mr. Abdoulaye Wade, warned that he would withdraw his soldiers if it is determined that the targeted peacekeepers were not equipped to defend themselves.

The peacekeeping force is already understaffed and under-equipped. The head of the Nigerian forces conceded that they were "outgunned" and "outnumbered." It is estimated that there will be only 8,000 troops in the field by the end of the year, and it is doubtful that they will be of the caliber needed to support the mission. Only Jordan has promised the aircraft that are necessary to patrol an area the size of France.

The United Nations has condemned the attack on the peacekeepers. The denunciation was less forceful than some wanted because there was uncertainty about who was responsible. Fingers were pointed in both directions, with rebels blaming the government and the government blaming rebels. Both denied any involvement in the attack.

Most of the evidence points to rebel involvement. That poses a problem for those who want their conflicts neat, with good guys and bad guys clearly defined. Sadly, the situation in Darfur is anything but neat. With peace talks scheduled to begin in a few weeks, it must be clear that no party will enjoy impunity if they endanger the peace and threaten innocent civilians. There can be no indifference to or toleration of any violence. That is the starting point for real peace in Darfur. There is a long way to go.