DRC:Rwanda is supplying a renegade Tutsi general in eastern Democratic Republic of Congo with ammunition and personnel as he seizes control of parts of the region and attacks government forces, according to UN security officials.
Gen Laurent Nkunda's troops have occupied an area along the border with Rwanda and Uganda.
Men and equipment have been observed crossing into Congo, which has already endured 10 years of war during which some four million people have died.
UN officials said Gen Nkunda's forces appeared to be strengthening their control along the border in a move to secure supply lines. They have also moved their families to the area.
The general broke away from the national army last week - nine months after his forces were integrated into it - after accusing the government of collaborating with Hutu extremists responsible for the 1994 genocide of Tutsis in Rwanda, who then fled into Congo.
The UN has helped the government to fly in additional troops and ammunition to North Kivu, in part to defend Goma.
Gen Nkunda said at the weekend that he was in a "state of war" with the government in defence of eastern Congo's Tutsi population.
But the government in Kinshasa believes he is a proxy for Rwanda, which it says is intent on maintaining instability in the east of the country where it has financial interests in illegal mining.