KAMPALA, Uganda -- Regional leaders met in Uganda Saturday in the latest summit intended to find a solution to the crisis in eastern Congo as the M23 rebel group takes territory from the army and threatens to topple President Joseph Kabila's government.

Uganda, whose leader is acting as a mediator, has had its credibility tarnished by revelations in a U.N. report that some of its military officials actively support M23 rebels, who this week took control of the provincial capital Goma as well as the city of Sake in Congo's east. Rwanda is also accused of supporting the rebels. Both countries deny the charges.

Kenyan President Mwai Kibaki and Tanzanian President Jakaya Kikwete also attended the Kampala summit, which is being held under the auspices of a regional bloc called the International Conference on the Great Lakes Region, or ICGLR, of which Congo is a member.

A previous summit of the ICGLR endorsed the creation of a "neutral international force" to police eastern Congo. Tanzania has already offered to contribute some of the 4,000 troops needed, but the force's mandate is not yet clear and funding remains a problem. Ugandan diplomats said regional leaders were likely to talk in detail about the force.

Kabila was in Uganda for the talks Saturday, but Rwandan President Paul Kagame was absent. Ugandan officials said M23 representatives were not invited to the summit and denied reports that Jean-Marie Runiga, the M23's political leader, was in the country for separate negotiations with the Ugandan government.

"I have not seen them," Crispus Kiyonga, Uganda's defence minister, who held meetings with some M23 officials before Goma was captured by M23, said of the rebels. Ugandan officials say previous meetings with M23 rebels were held with the knowledge of Kabila, who at first declined to negotiate with the rebels but later changed his stance.

"This is a summit for regional leaders, not a negotiation meeting. The rebels cannot be in the summit," said Okello Oryem, Uganda's deputy minister of foreign affairs.

M23 is made up of hundreds of officers who deserted the Congolese army in April. Since then the rebels have occupied vast swaths of territory in mineral-rich eastern Congo, and their capture of Goma this week put pressure on President Joseph Kabila to negotiate with the rebels, who accuse his government of failing to honour the terms of a 2009 peace deal that incorporated them into the national army. The rebels took Goma without much of a battle, with the Congolese army fleeing in disarray and U.N. peacekeepers holding fire.

M23 leaders insist they will attempt to capture the Congolese capital of Kinshasa if Kabila does not negotiate directly with them. Uganda's President Yoweri Museveni, Congolese President Kabila and Rwanda President Kagame said in a statement Wednesday that they would not tolerate M23's talk of toppling the Kinshasa government, demanding that the rebels pull out of Goma and make a retreat. But the rebels went ahead and took Sake.

"In solidarity with the Congolese people and their counterparts, President Yoweri Museveni and President Kagame made it clear that even if there were legitimate grievances by the mutinying group known as the M23, they cannot accept expansion of this war or entertain the idea of overthrowing the legitimate government of the DRC (Congo) or undermining its authority," the presidents' statement said. "Therefore the M23 rebel group must immediately stop its offensive and pull out of Goma."

On Friday, Congo's president suspended the army chief of staff following the publication of a United Nations report which reveals that Gen. Gabriel Amisi oversaw a criminal network selling arms to rebels in the country's troubled east. The rebels also took the town of Sake.

Congo's troubled east has been plagued by decades of violence, and the latest rebellion is a reincarnation of a previous conflict. The rebel group that took Goma dubs itself the M23, a reference to the March 23, 2009 peace deal that paved the way for fighters from a now-defunct rebel group to join the army. Charging that the peace accord was not implemented, soldiers defected from the Congo army in April to form the M23. Both the M23 and the previous rebel group, known as the CNDP, are widely believed to be backed by neighbouring Rwanda, which has fought two wars against its much-larger neighbour.