ZAM ZAM CAMP, NORTH DARFUR
SUDAN'S troubled western region of Darfur has deteriorated back into a state of anarchy and bloodshed, hampering humanitarian work, according to senior United Nations officials.
Thousands of people have arrived at the region's sprawling aid camps after rebels and government-backed Janjaweed militia stepped up attacks during the past six weeks.
And the UN's World Food Programme (WFP) is warning that November's harvest will be disrupted if the violence continues.
Jan Pronk, the UN's special representative to Sudan, speaking in Khartoum, said: "We have had a relative calm in Darfur since April, but in the past six weeks things have deteriorated."
He explained that rebel commanders and their Janjaweed counterparts had lost control of their troops.
At the same time, a split within the Sudan Liberation Army (SLA), the main rebel movement, had seen rival commanders step up military action in order to win influence.
"It is a sort of anarchy," said Mr Pronk.
Nowhere is this new phase of violence more visible than North Darfur.
SLA rebels attacked the village of Almallam at the end of September, escaping with dozens of cattle and camels.
The Janjaweed responded swiftly, taking revenge on as many as 50 villages.
One of those was Sandingo. They arrived on a Sunday evening as the men of the village were listening to a cleric from Chad.
The gunmen swept into the village on horseback and riding in Toyota Landcruisers, according to Mohamed Ibrahim Adam, 37.
The men ran for their lives, gathering women and children from the mud-brick homes of the village as the Janjaweed fired AK-47s indiscriminately.
"They killed 12 men and injured seven more," said Mr Adam. "We had to run into the hills and then come here [Zam Zam]." His family arrived in Zam Zam last week. It is a sprawling camp of mud-brick huts roofed with plastic sheeting on the outskirts of El Fasher, the capital of North Darfur.
Some 5,000 people have trekked here in the past six weeks and a further 1,900 have arrived at neighbouring Abu Shouk. Zam Zam is now almost full.
New arrivals must mark out a small patch of ground with stones as they wait for help building a shelter.
Mohamed Nasir Abdullah, an elderly man, spends his days sitting within a pebble ring beneath an acacia tree to keep off the burning sun.
"I am new, so I don't have any shelter. This is my house," he says, indicating the dusty soil around him.
It is two and a half years since the farming tribes in the western region of Darfur took up arms against the Arab government in Khartoum, which they accused of ignoring their needs.
The Sudanese government responded by unleashing nomadic Arab militias - the dreaded Janjaweed - on the rebels.
The militias, often backed by government Antonov aircraft, razed villages they suspected of harbouring rebels.
Conservative estimates suggest that two million people have fled their homes for camps, where international charities offer a measure of security. A further 180,000 people have been killed.
All sides have stepped up the violence in the latest escalation, which coincided with the resumption of peace talks in the Nigerian capital Abuja last month.
In West Darfur, aid workers are confined to the capital, as the United Nations has declared all roads out of bounds due to banditry.
African Union troops sent in to observe a much-ignored ceasefire are finding themselves increasingly targeted; five Nigerian soldiers and two civilian contractors were killed last month.
The WFP says that each day a food truck is looted, fired upon or harassed.
And last week tensions in Darfur's largest camp, Kalma, boiled over. Residents frustrated by a government blockade of the site and the arrest of a tribal leader took 35 Sudanese contractors and a handful of aid workers hostage, later releasing them unharmed.
One charity worker summed up feelings among the aid community: "We are getting it from all sides."
Where once the rebels were seen as co-operative, he added, now they are as likely to cause problems as government forces. "There has been a total breakdown of law and order, and people are taking advantage."
November is harvest time, but with many farmers trapped in camps, much of this year's crop could go to waste.
Zam Zam is full of farmers who have left behind fields of tomatoes, watermelons and sorghum, the main staple.
"I need to get back, but there's no security," says Abaka Hassan Abdullah, 27, from Sandingo. "The harvest is coming and we are all worried that it will be taken by the Janjaweed."