Congolese government forces clashed with rebels at a town near the border with Rwanda for a third day on Wednesday as the two countries traded heated accusations over who was involved in the fighting. The clashes broke out as government reinforcements -- sent to the region after Rwanda threatened to invade -- tried to move southwards, United Nations peacekeepers said. The fighting in the town of Kanyabayonga involves members of the RCD Goma group, a Rwandan-backed rebel faction during Congo's five-year war. It is now officially part of the army but remains largely separate from the national military command. "The fighting started early this morning and continued all day long. But by 4 p.m. it seemed to be calming down," said Jacqueline Chenard, a U.N. spokeswoman. She said RCD Goma remained in control of the town. Congolese officials have accused Rwandan troops of taking part in the clashes, and President Joseph Kabila's spokesman said Congo was "at war" with its neighbour, although other government officials played down the remark. Rwanda has denied any of its soldiers are in eastern Congo, although it says it reserves the right to go in and hunt down Rwandan Hutu fighters, some of whom took part in their country's 1994 genocide before fleeing into Rwanda's western neighbour. Pakistani peacekeepers fired shots overnight to repel three boats of gunmen crossing Lake Kivu towards the Congolese town of Bukavu from Rwanda, said Iliane Nabaa, another U.N. spokeswoman. "They fired some warning shots but the men in the boats fired back," she said. "The exchange of fire lasted about 10 minutes before the boats turned around and went back to Rwanda."