Janjaweed militias have focused their wrath on innocent villagers for most of the two and a half years of the conflict in the Darfur region. But on Sept. 18, in a scene that aid workers described as something out of a Hollywood western, the militiamen surrounded the police station along Sudan's border with Chad, roughed up the chief and freed several of their members from jail.

The fact that militias trained and armed by the government are now emboldened enough to turn their guns on the government is a sign of trouble. It was government support of the janjaweed at the outset that ignited the fighting in Darfur that killed tens of thousands of people and displaced two million villagers.

The standoff in Geneina, which together with other incidents prompted the United Nations to evacuate many of its personnel, is part of an overall deterioration in Darfur. The conflict has grown even more confused and chaotic in recent months. Now, rebels fight other rebels, the ties between some janjaweed fighters and the government have frayed, and the African Union troops charged with quelling the conflict find themselves targets as well.

"Darfur is no longer under control," said Eltayeb Hag Ateya, head of the Peace Studies Institute at the University of Khartoum. "It's not just the government against the rebels anymore. There's this armed group and that armed group. It's getting more complicated by the day."

The war here was never a straightforward one. It was part Arab versus African, part government versus rebel, part nomad versus farmer. But two rebel forces have now grown to five or more, with some fighters from neighboring Chad adding to what one aid worker in Darfur called "a cocktail of armed actors."

Some janjaweed fighters have put on government uniforms. Others maraud through the countryside taking orders from no one. With peace talks at a critical stage, the number of fighting forces jockeying for power seems to grow by the day.

Zam Zam, a former village in northern Darfur that has been transformed into a sprawling camp of people on the run from war, is one place that illustrates the new Darfur.

Things in Darfur can be deceptively calm at times - until hundreds of men on camelback come loping through the sand with their guns blazing. Or until rebels leap out from their cover in a surprise attack on government troops. Or until a government aircraft swoops in low.

Darfur's war began when two rebel groups opened attacks on the government in early 2003, accusing it of ignoring African tribes of Darfur. The Islamist government struck back, enlisting the aid of Darfur's Arab tribes. The militias destroyed hundreds of villages throughout Darfur, raping and pillaging as they sought to root out rebels and punish sympathizers.

Zam Zam, created in 2003, grew into one of Darfur's largest camps for internally displaced people. It has always been an insecure place, situated strategically near government and rebel strongholds. But something happened earlier this year that gave aid workers hope that Darfur might be changing for the better.

The population of the camp, which has crept higher and higher since the fighting started, finally began to drop. In May and June, hundreds and then thousands of people in Zam Zam and other camps around Darfur began returning home to cultivate their crops, a sign that normal life was returning to this desperate place.

But the hopeful signs did not last long. Just last month, after the villagers had hoed their plots and planted their vegetables and groundnuts and other crops, the militias attacked again.

"They came with cars, with horses and with camels," said Ali Mohamed Fadu, a sheik from Jabein, a village that was overrun on Sept. 17 for the second time in two years. "They all had guns, and they shot at us and killed some of us."

The accounts offered by villagers are remarkably similar to the ones heard at the start of the conflict, when people across Darfur were terrorized in attacks that the United States government said amounted to genocide.

With villagers on the run again, the population of Zam Zam is back on the rise, with thousands of new arrivals in the past three weeks.

Ismail Abduraman, 25, lost his father, who was a shopkeeper, in the recent attacks. After robbing him and shooting him, the militiamen looted his shop. In all the confusion, Mr. Abduraman became separated from 17 of his brothers and sisters.

While most people in Darfur contend that the countryside is far too dangerous for them these days, Mr. Abduraman is planning to return in search of his missing family members. He plans to take a donkey along and walk seven hours to the west, across the scorching sand.

"I have to go," he said. "I can't just sit here when my family is out there. My father would go, but he can't. I'm the elder now."

Farther east, in Tawila, the situation is similarly grim. African villagers congregate on the south side of the main road together with some fighters from the Sudan Liberation Army, the main rebel movement in Darfur. To the north is a police station where many of the officers are former militia fighters.

It is an explosive mix that has led to a series of shooting incidents in recent weeks. Terrified people from the area now huddle next to the African Union camp overlooking the town.

But the African soldiers are hamstrung by their rules of engagement, their lack of equipment and their inexperience in the field. When the police recently raided Tawila, shooting at suspected rebels and burning structures in the market, African Union soldiers watched from their hilltop perch but did not intervene.

It is impossible for them, however, to remain entirely on the sidelines. An African Union convoy was ambushed on Oct. 8 in the Khorabashi area in South Darfur. During an exchange of fire, four Nigerian soldiers and two civilian contractors were killed.

A day later, a renegade group of rebels abducted 38 African Union soldiers in the border town of Tine, warning the African Union not to tread in its territory. The soldiers were rescued after a battle between rival factions of the Justice and Equality Movement, which is one of the rebel groups opposed to the Sudanese government in Darfur.

Baba Gana Kingibe, the African Union's special representative in Sudan, said recently that there was "neither good faith nor commitment on the part of any of the parties."

Perhaps the most horrifying incident in the new Darfur occurred along the Chadian border at the Aro Sharow camp. On Sept. 28, several hundred janjaweed fighters raided the camp, killing 35 people and wounding 10 more. Most attacks occur for a reason here, and this one is believed to be tied to the killing of a janjaweed leader's children days before or, in another version, the theft of hundreds of camels from Arab tribesmen by rebel fighters.

If there is a hopeful sign in Darfur, it is this: Violence typically spikes in such conflicts when peace talks reach a critical phase. The negotiations in Abuja, Nigeria's capital, are in their sixth round, bogged down but not broken. The recent brutalities are seen as efforts by various fighting forces in Darfur to win a seat at the table or at least get access to some of the spoils.