For the past three years, Arab militiamen have helped Sudan's government quell a rebellion in Darfur by slaughtering the region's mostly black African population and leaving behind a trail of rape, murder, and destruction. The result: more than 200,000 dead and 2 million displaced in what the United Nations calls the world's worst humanitarian emergency.
At the very least, however, the violence in western Sudan was mostly confined to its borders.
The crisis in Darfur has exploded in recent weeks, and now threatens to drag fragile neighboring countries into a regional war.
Both Chad and the Central African Republic (CAR) have become engulfed in fighting that involves a toxic mix of rebel groups, government forces, armed militias, and civilians.
"It's not a steady deterioration," Jan Egeland, the outgoing UN humanitarian chief, told reporters last week. "It's a free fall, and it includes Darfur, eastern Chad, and northern Central African Republic."
In the past month alone, nearly 60,000 Darfurians have been forced from their homes to escape massacre at the hands of Arab militias known as the janjaweed. Aid workers, UN personnel, and independent observers say the janjaweed are backed by Sudan's government, but Khartoum has repeatedly denied this charge.
In eastern Chad, hundreds of aid workers have been evacuated due to increased hostilities between military forces and anti-government rebel groups, while Arab militiamen have ventured deeper into the country to conduct assaults, resulting in the displacement of nearly 100,000 Chadians.
And atrocities committed by a variety of rebel groups and armed bandits over the past few months have forced tens of thousands of people from the CAR to cross the border into Chad.
"The internal conflicts in Darfur, Chad, and the CAR are now linked by the regional presence and movement of armed groups, arms, and civilians across the three borders," said Georgette Gagnon, deputy director of the Africa division of Human Rights Watch. "And of course, the regional governments are using these insurgencies to carry out a proxy war against each other."
Indeed, leaders in Khartoum, Sudan's capital, and N'Djamena, its Chadian counterpart, have traded accusations as to who is responsible for stoking the bloodshed that has plagued Darfur since 2003. Both countries blame the other for supporting rebel groups.
In the past two weeks, the fighting has become so severe that hundreds of aid workers have been pulled from the region, leaving behind the displaced Sudanese, whose plight is now especially grim.
"For sure, if this situation lasts it will have a greater direct effect on the refugees' lives," said Hélène Caux, a spokeswoman for the United Nations High Commissioner of Refugees (UNHCR).
Since the last week of November, nearly 500 aid workers have been relocated from Abéché, the eastern city that serves as the hub for relief agencies in the region, to N'Djamena, while more than 100 are still awaiting evacuation from Guereda, a town farther north, according to the UNHCR.
Aid officials concede that, with only the skeleton crews now left behind in camps across the east, the refugees' situation has become particularly precarious.
"We haven't seen any downfall or deaths as a result of the reduction in personnel," says Joseph Aguettant, of the International Rescue Committee (IRC), which has trimmed its international staff in Bahai, a city along Chad's northern border, by 80 percent. "But we know this is something that can happen."
The area around the Goz Amir refugee camp, about 60 miles from the border, has become so rife with attacks that the Sudanese refugees and Chadians living nearby are stricken by fear of being set upon by the Arab militias.
Men head into the bush carrying bows and arrows, while young boys walk around with spears that are often taller than they are. When asked why they have the weapons, the response is unanimous: "defense."
The janjaweed – joined at times by Chadian Arabs – have been laying siege to villages east of Goz Beida, a Chadian town 100 miles from the Sudan-Chad border. The locals who survive are forced to trek miles to the closest villages, which often are plundered days later. They are then forced to flee yet again, and often end up setting up makeshift camps on wide swaths of parched land that offer little more than dust and thorn trees.
Hawaye Ismail arrived at just such a place, an open field 25 miles east of Goz Beida, last week with about 600 others. "We don't have anything to eat, and look, there's death all around us," she says.
Ms. Ismail's village was torched by Kalashnikov-carrying Arabs on horseback and camels in early November in an ambush that left 14 men dead. She made it to a nearby village, but was left homeless days later after the raiders rampaged again.
"The young attackers abused the young girls and the women," Ismail says, gesturing to the half-dozen women in tattered clothes gathered around her. "Today, with our situation, only God knows what we've been through."