Rwanda's foreign minister said Saturday that neighboring Congo (search) has massed thousands of troops on the border and is preparing to attack his country.

Foreign Minister Charles Muligande said the troops include Rwandan rebels who fled to Congo after playing a central role in the 1994 genocide (search) in Rwanda (search).

"This heavy deployment of Congolese soldiers and Rwandan rebels is a big threat to the security of our country," Muligande said. "Certainly we shall not sit back and watch these developments."

Congo's Deputy Minister of Foreign Affairs Henry Mova Sakanyi dismissed the allegations as "fabrications" and repeated claims that Rwandan troops were in Congo in violation of a peace deal.

Earlier this month Congo accused Rwanda of backing renegade Congolese troops who seized control of the strategic eastern city of Bukavu for a week. Rwanda denied the charges.

Rwanda sent troops into Congo in August 1998 to help Congolese rebels oust then-President Laurent Kabila. Rwanda accused Kabila of supporting Rwandan insurgents involved in the slaughter of at least 500,000 minority Tutsis and political moderates from the Hutu majority.

Rwanda withdrew troops from Congo in November 2002 after Congo agreed to disarm Rwandan insurgents based in the country and hand them over to Rwandan authorities.

Rwanda has since complained that Congo has failed to keep its side of the peace agreement.