Tribal fighters controlling this shattered northeastern town are withdrawing to outlying camps ahead of the arrival of a French-led emergency force to stabilize the region after hundreds were killed in fighting, U.N. officials said Tuesday.

The pullout began as U.N. Secretary-General Kofi Annan (search) called for nearly tripling the number of U.N. troops in this corner of Congo to help end tribal fighting in a new effort to promote a peace deal to end the country's internal conflicts.

Some 600 fighters of the Union of Congolese Patriots (search), or UPC, moved to barracks outside town Monday, Col. Daniel Vollot, commander of U.N. troops in the region, said.

The UPC said that its 15,000 troops deployed in and around Bunia (search) would be confined to barracks outside town, Madnodje Monoubai, a spokesman for the U.N. mission to Congo, or MONUC, said.

The UPC withdrawal is part of a cease-fire deal signed by five rival Lendu and Hema tribal groups and the Congolese government -- all of whom have been fighting for control of Bunia, capital of the mineral-rich Ituri province.

The deal commits the warring factions to demilitarize Bunia and confine their fighters to temporary quarters.

The vanguard of the French-led force of some 1,400 troops is expected in Bunia at the weekend following the May 30 authorization by the U.N. Security Council.

Annan has called for new measures, including a possible arms embargo, to deal with conflicts in Ituri and North and South Kivu provinces. The conflicts are threatening efforts to set up a broad-based government in Congo that would govern during a two-year transition to the first democratic elections since independence from Belgium in 1962.

Fighting between the Hema and Lendu tribes has killed over 500 people in Bunia since Ugandan troops pulled out on May 7.

Annan said a 3,800-strong U.N. peacekeeping force should replace the French-led international force some time in September.