Armed with heavy automatic rifles and a rocket launcher, 18 African Union peacekeepers warily patrol Zamzam, a sprawling camp of thatched huts and makeshift tents where some 40,000 people have sought refuge from Darfur's violence. Their numbers were no match for the thousands of armed men in the area from a dozen warring factions.

The AU is desperately short on men and material and viewed with increasing suspicion among some of the Sudanese it was sent to protect. Despite a peace accord between the government and rebel groups, the United Nations and aid groups say violence has worsened in the past few weeks — leaving many to wonder whether the international community can bring calm to the battle-scarred land.

The main faction of the rebel Sudan Liberation Movement originally signed the May 5 accord with Sudan's government, but a splinter faction held out until Thursday, along with a faction of the Justice and Equality Movement.

The U.N. Security Council and the AU have agreed that a U.N. force should take over operations in Darfur and that the 7,000 African troops now on the ground in Darfur must be reinforced quickly. But Khartoum has been reluctant to accept a U.N. force, and security in the region remains precarious.

"With all the splinter rebel groups, the Janjaweed controlled by the Sudanese army and those who act own their own, there are maybe 20 armed factions in this zone," said Lt. Col. Mohammed Sallam, an Egyptian officer who commands AU military operations in the Zamzam area.

"When you get in an ambush, you know you are being shot at, but you never know by who."

Decades of low-level clashes in Darfur over land and water erupted in early 2003 when rebel groups of ethnic Africans rose up against the Arab-led government in Khartoum. The government is accused of responding by unleashing Arab militias who have been accused of committing atrocities against the African population. The government in Khartoum denies any involvement.

The three-year conflict in the western region of Darfur has claimed at least 180,000 lives and forced more than 2 million people to flee.

As the Security Council visited the region and a joint assessment team began to study how to replace the African force with United Nations troops, the sheer lopsidedness between peacekeepers — barely 50 of them in Zamzam on a good day — and combatants illustrated the difficulty of ending the chaos in Darfur.

Unknown militias killed an AU soldier in an ambush last month and seriously wounded several others in a separate rocket attack on an AU base. An interpreter also was recently slain — by the very refugees the African force came to protect.

In Zamzam, officers say they never leave their small police office without a military escort.

"We're scared. The situation is completely unpredictable here," said Lekbaraki Salem, a Mauritanian police officer. He said he suspected there were many weapons in the camp, and that combatants from the Sudan Liberation Movement — the region's main rebel group — crossed the lines at night to visit their families.

Most SLM rebels in the area belong to the Zaghawa tribe, as does rebel chief Minni Minnawi, who signed the peace agreement. But most of the refugees in Zamzam belong to the Fur, a large tribe that gave its name to Darfur and mostly follows dissident rebel leader Abdulwahid Elnur — who refuses to endorse the accord.

Although the treaty has not prevented increased fighting between rival SLM factions to the west and to the north, there has not yet been any violence inside the Zamzam camp.

Still, communication is a problem. The peacekeepers said many refugees who support Elnur's faction blame the AU for the treaty, which they consider unfair. While several translators at the nearby El Fasher headquarters complained they were underworked, the AU military patrol Friday did not include a single Fur or Arabic speaker.

"We have to explain it (the treaty) better to them," said Maj. James Mulenga, a Zambian officer with the AU. A group of Zaghawa and Fur sheiks said they would be eager to return to their villages if security improves, and hoped to be compensated for their loss. But they didn't want to discuss the peace agreement, and AU peacekeepers insisted on leaving before the gathering grew hostile.

In Zamzam, Hawatilin Hamid said finding wood for cooking was one of her hardest chores. AU soldiers once accompanied women gathering wood, but such patrols were stopped because of the growing hostility among many refugees toward the African force.

Hamid, a 45-year-old widow, said she was so worried about being raped by the Janjaweed roaming outside the camp that she used money earned cleaning the house of another villager to buy firewood, rather than extra food for her five children.

"We have to survive on the aid rations," she said. "That's one kilo (2 pounds) of wheat for each of us every month. I don't know how long we can last."