An aid group on Sunday sent the first medical supplies to a ravaged eastern Congo since fighting ended there, as officials in the provincial capital of Goma clamped down on the illegal sale of food aid in the city's bustling markets.

Rebels led by Laurent Nkunda captured the two towns from the government 10 days ago in a swath of territory that allowed him to link up positions won in the latest round of a long-simmering rebellion that erupted in August. The fighting has uprooted some 250,000 people, who have taken shelter in camps or anywhere they can get away from the violence. Getting supplies to them has been very difficult.

Goma mayor Roger Rashiy said local police spotted sacks of maize flour bearing the World Food Program logo in the local market, which led to the seizure of some 40 tons of food aid and the arrest of several vendors. Authorities said the food will be returned to aid agencies to be distributed.

"It's the first time I've seen this," Rashiy said.

Officials of the U.N. agency said the food on sale comprises about one percent of the 3,500 metric tons of food aid they have given to the hundreds of thousands of refugees living in and around camps in Congo's North Kivu province.

"We are aware that a small portion of our food may be sold in the market," said agency spokeswoman Caroline Hurford. "This happens in all emergencies, and it's largely because the beneficiaries like to diversify their diet. They're tired of eating the same thing, which is understandable."

North of Goma, the distribution of US$300,000 worth of medical aid resumed for 40,000 people trapped in rebel-held land after last week's territory grab by the rebels.

London-based medical aid group Merlin took a truckload of basic medication to 20 clinics around the towns of Kanyabayonga and Kirumba, more than 60 miles (100 kilometers) northeast of Goma, for the first time since they were captured during a rebel advance.

"We're really pleased that we've gotten here," said Merlin spokeswoman Louise Orton. "We haven't been here for a week and a half. We know the health centers really need the drugs."

Local human rights groups accuse Laurent Nkunda's rebel forces of raping and murdering civilians and abducting young men to fight against the government - accusations he denies.

Nkunda says he is protecting Congo's minorities, especially ethnic Tutsis he says are threatened by Hutu militias from Rwanda, many of whom fled to Congo's forests after participating in Rwanda's 1994 genocide. Critics accuse Nkunda of exploiting the instability to gain power, and say his attacks have increased resentment against Tutsis.

The United Nations has 17,000 peacekeepers in the Central African nation and has approved the deployment of a further 3,100 but the government, whose ill-disciplined and badly trained forces have frequently fled the fighting, is refusing to negotiate with the rebels.

On Sunday, hundreds of angry Congolese soldiers dragged 25 men who they claimed were rebels from a U.N. convoy of canvas-covered trucks driven by Indian peacekeepers. The men said they were government policemen from rebel-held areas. A few wore faded navy blue uniforms, with "police" embroidered on the pocket.

The U.N. troops driving the trucks did not intervene as the men's hands were bound behind them with string and they were driven away from the checkpoint near Kibate, a refugee camp four miles (six kilometers) north of Goma.

A U.N. spokesman did not have any immediate comment on the incident and U.N. soldiers on the scene would not talk to The Associated Press. It was not clear why the men were on the convoy.

In a separate incident, a Ugandan army officer said his country had on Saturday handed back 35 Congolese policemen who had fled the fighting because they had carried their weapons into Uganda.