GOMA - UN forces will "do the maximum" to protect civilians in rebel-threatened Goma, the organization’s top peacekeeping official vowed Monday as aid workers found camps in rebel-held areas had been razed and emptied.

Alain Le Roy said UN troops were continuing to reinforce their presence in the city, under siege from Tutsi rebels led by renegade general Laurent Nkunda who have routed government forces in eastern DR Congo's Nord-Kivu province.

But in a scathing assessment following a weekend visit to the region, France's Foreign Minister Bernard Kouchner said the UN force as currently constituted was powerless to stop the rebel advance.

The UN needed different soldiers and rules of engagement to tackle them, he added.

Arguments about the force's effectiveness raged as a UN aid convoy allowed into rebel-held territory found camps near the town of Rutshuru, in the northern part of Nord-Kivu, empty.

"We visited three camps in the Rutshuru area," said Sean Rafferty of British charity Merlin after arriving in the rebel-held town on Monday in a convoy escorted by UN troops.

"We would have expected a population of 11,000 people, but all the camps are empty. The camps were completely leveled. None of the materials were there. We are very concerned about the welfare of those people.

"Our priority is to find out where they went, so that we can get them assistance," he said.

It was the first time aid agencies had been able to reach Rutshuru since the UN last week said that 50,000 people had gone missing after "credible reports" that rebels had looted and burned camps around the town.

The UN's Office for the Coordination of Humanitarian Affairs (OCHA) confirmed the camps were empty.

"We saw two empty camps. They are completely empty. There is no shelter," said Francis Nakwafio, OCHA coordinator in Rutshuru.

Rutshuru is about 80 kilometers (50 miles) north of Goma where Le Roy, speaking to reporters during a visit with UN mission chief Alan Doss, said the MONUC peacekeeping force's mandate was clear: "to stop armed forces from entering Goma."

Le Roy said the UN force was working on "redeploying forces to where they are most useful and where the crisis is stronger at the moment."

Rutshuru is one of several key towns taken since August by Tutsi rebels led by Laurent Nkunda in an offensive that has displaced 1.6 million people and brought them to the threshold of Goma before declaring a ceasefire last week.

Authorities declared a curfew in Goma on Monday. The curfew, which will come into effect from 11:00 pm (2100 GMT) to 5:00 am (0300 GMT), follows a spate of murders, rapes and lootings last week blamed on out-of-control elements of the government army.

Kouchner, speaking following talks with his 26 EU counterparts in Marseilles, southern France, said: "Do we need more soldiers? Possibly. In any case we need different soldiers, and different rules of engagement, and a different spirit of command.

"There are entire brigades that are unable to engage in defensive, let alone offensive, action, because their rules of engagement are insufficient or they are very restrictive," Kouchner said.

The minister, whose country holds the rotating EU presidency, last week suggested mobilizing an EU battle group of up to 1,500 troops to provide humanitarian assistance for refugees displaced by fighting.

Kouchner returned Sunday from a trip to Kinshasa and Kigali with his British counterpart David Miliband to try to broker an end to the unrest in eastern DR Congo.

Nkunda has threatened to oust the government in Kinshasa unless it holds "direct" talks on his demands.

The government rejected his demands, saying it saw no reason to discriminate against "other groups of Congolese who have propositions to make" on the crisis in the country, according to a spokesman.

Nkunda has said he will not negotiate as part of the ceasefire. He wants "the re-establishment of security" with stronger action against Hutu rebels from neighboring Rwanda; the setting up of a "Republican national army"; and "greater transparency" in the awarding of mining contracts.

He again denied receiving support from Rwanda. The Kinshasa government has accused Rwanda's ethnic Tutsi-dominated government of backing Nkunda's rebels.

Rwanda has also denied the charge, but analysts say the Kigali government -- frustrated by its neighbor’s failure to disarm Rwandan Hutu rebels, the FLDR, harboring perpetrators of the 1994 genocide against Tutsis -- is helping Nkunda.