Rwandan and Ugandan troops fought street battles in the eastern Congolese city of Kisangani yesterday, trapping civilians in their homes.
Leaders of both Uganda and Rwanda were scheduled to meet yesterday afternoon to bring order to rebel-held Kisangani but their ground forces continued to fight throughout the morning.
"The fighting is still going on with the use of heavy weapons and mortars," Mr Ernest Wamba dia Wamba, the leader of the Ugandan-backed Congolese rebel faction, said by satellite telephone.
He said fires were burning across the city. He did not have details of casualties but expected them to be "very heavy" among both civilians and soldiers.
The fighting began on Saturday night at the city's international airport and spread into the city. Each side blamed the other for starting it. Uganda and Rwanda were allies in recent years but now support rival factions in a year-old rebel war they are both sponsoring against the Congolese President, Mr Laurent Kabila.
The clashes follow battles in the city last weekend between Rwandan-backed rebels from the Congolese Rally for Democracy (RCD) and Ugandan troops backing the splinter RCD faction led by Mr Wamba, who was ousted from the group's leadership in May. Rivalry between the factions blocked the rebels from signing a peace accord brokered on July 10th in the Zambian capital, Lusaka.
"Kisangani was a town that was run by the RCD and controlled by the Congolese rebels. But last week Ugandans went and shot them out of their positions to install Wamba there and that has created a severe atmosphere of tension," said Mr Patrick Mazimhaka, Rwanda's minister of state in the president's office.
Mr Wamba offered a different version. "The Rwandese army set up a road-block on the way from the airport and opened fire on Ugandan troops who responded."
The fighting is threatening a UN-backed campaign to vaccinate some 10 million children against polio, the Congolese government said. The Health Minister, Mr Mashako Mamba, said on Sunday the fighting had disrupted electricity in Kisangani, ruining three million refrigerated doses of vaccine.