The Rwandan military is backing a rebel group that has battled Congolese forces and U.N. peacekeepers in eastern Congo, a flagrant violation of U.N. sanctions and the terms of a fragile peace accord, an unpublished U.N. report says.

The 49-page report, which was prepared by a panel of four U.N. sanctions experts, also charges that Rwandan troops forcibly entered a U.N.-controlled refugee camp in Cyangugu, Rwanda, rounded up 30 young men and pressed them to join the Congolese rebels. They were released after officials from the Office of the U.N. High Commissioner for Refugees protested, according to the report, scheduled for release on Tuesday.

A rebel force headed by two renegade Congolese officers, Col. Jules Mutebutsi and Brig. Gen. Laurent Nkunda, first emerged as a threat to the delicate Congolese peace process in early June, when more than 3,000 troops seized control of the strategically important town of Bukavu in eastern Congo, the report says.

The capture of Bukavu sparked nationwide protests against the government of President Joseph Kabila and the United Nations, whose force of 400 U.N. peacekeepers in Bukavu was unable to repel the attack. U.N. officials have expressed concern that it may also mark the beginning of a trend in which former rebel leaders who joined Congo's transitional government in June 2003 take up arms again.

The followers of Jean-Pierre Bemba, a former rebel leader who was appointed vice president of Congo's transitional government, are transporting a "considerable amount" of heavy weapons and ammunition on Bemba's private planes to the airport in Gbadolite, the report says. It adds that Bemba's troops have barred U.N. military observers from entering the airport.

The Congolese government reacted to the attack on Bukavu by accusing Rwanda of backing the rebels, and by deploying more than 8,000 troops in the region to drive the rebels out of Bukavu. The United Nations, which has 10,800 peacekeepers in Congo -- formerly called Zaire -- sent about 900 additional peacekeepers to Bukavu to help restore calm.

Stanislas Kamanzi, Rwanda's ambassador to the United Nations, said the allegations that his government aided the rebels, which were first reported by Radio France Internationale, "are not true. We were not involved in this crisis in the DRC [Congo] in terms of supporting the dissidents."

Congo, a former Belgian colony, was the scene of Africa's deadliest regional war in 1998. Troops backed by Rwanda and Uganda sought to topple Congo's ruler then, Laurent Kabila, a man they had helped bring to power.

Angola, Namibia and Zimbabwe entered the war on behalf of the Congolese leader. Under the 1999 peace accord reached in Lusaka, Zambia, the five countries agreed to withdraw their troops from Congo.

The Security Council in July 2003 imposed a ban on military and financial support for armed groups in eastern Congo. A panel was set up to monitor compliance.

After the attack on Bukavu, the U.N. panel traveled to eastern Congo and Rwanda in two teams, collecting evidence on the armed groups' ties to Rwanda and documenting Rwandan violations of the embargo on military assistance to such groups in eastern Congo. The panel said it was "highly likely" that the rebels were supplied with weapons coming from Rwanda.

"Rwanda's violations involved direct and indirect support . . . to the mutinous troops," the new report says. "Rwanda has also exerted a degree of command and control over Mutebutsi's forces."

More than 150 rebels loyal to Mutebutsi retreated on June 8 into the Rwandan town of Cyangugu. They regrouped and crossed the border back into Congo, where they opened fire on a U.N. patrol in Kaminyola. The U.N. peacekeepers returned fire, forcing the rebels back into Rwanda.

"The group of experts observed that Mutebutsi had not disbanded his troops," the U.N. report says. "Approximately 300 of them, in uniform, remained in a coherent command structure under the protection of Rwandan troops."