The United Nations has said that its peacekeepers in eastern Congo have spotted some 100 soldiers it suspects of being members of the Rwandan army.

The sighting follows an appeal by Congo for an emergency meeting at the U.N. Security Council to impose sanctions on Rwanda for having violated Congolese sovereignty.

The U.N. mission in the Democratic Republic of Congo has announced that one of its patrols in eastern Congo on Wednesday spotted some 100 men it suspects of being soldiers in the Rwandan army.

A spokeswoman said that for now the mission could not confirm that the soldiers were Rwandans, but further patrols were being sent to investigate the area, just to the north of Goma, the capital of North Kivu province.

Ever since Rwanda last week threatened to send its soldiers into eastern Congo to hunt down Rwandan Hutu rebels, there have been allegations that Rwandan soldiers had already infiltrated across the border. Until Wednesday the United Nations had maintained that it has seen no evidence suggesting any Rwandan infiltrations. Initially, local sources and the Rwandan rebels themselves had made the claims. But on Tuesday the government in Kinshasa also publicly said that Rwandan soldiers had entered Congo.

Rwanda says it has the right to enter Congo to hunt down the rebels, many of whom it accuses of taking part in the 1994 genocide, killing 800,000 Tutsis and moderate Hutus before fleeing into eastern Congo. It says that neither the government nor the United Nations has been able to disarm the rebels that, Kigali says, are about to attack Rwanda. But Congo has reacted angrily and late on Tuesday Kinshasa called for an emergency meeting of the U.N. Security Council to condemn Rwanda's actions and impose sanctions on Rwandan President Paul Kagame and his close entourage. In a letter sent to the president of the Security Council, Congo has called for Mr. Kagame to be held personally responsible for violating Congolese sovereignty and threatening peace in the region.

Rwanda has invaded Congo twice before, ostensibly to hunt down the Hutu rebels. The last incursion in 1998 was one of the triggers for Congo's five-year war, which sucked in five other countries in the region and killed about three million people.

A transitional government has been set up in Kinshasa to lead Congo to elections in June next year, but there are fears that this latest crisis could derail the fragile peace process.