However, a senior army official said combat had not yet begun.
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Army spokesman General Leon Kasonga said the start of a campaign against the Democratic Forces for the Liberation of Rwanda (FDLR) was announced by the chief of staff of the Congolese army (FARDC), Didier Etumba, on a visit to the northeastern city of Beni.
The FDLR, whose estimated 1,400 fighters include ethnic Hutu soldiers who took part in Rwanda's 1994 genocide, have been at the heart of years of conflict in central Africa's Great Lakes region.
An attack on the group by the FARDC and the U.N. peacekeeping mission in Congo (MONUSCO) has been expected since the rebels missed a Jan. 2 deadline set by regional leaders to disarm.
Charles Bambara, spokesman for the U.N. peacekeeping mission in Congo (MONUSCO), said he considered Etumba's announcement a "green light" to begin operations.
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A 3,000-strong U.N. intervention brigade recorded significant successes in 2013 when it helped Congolese forces defeat Tutsi-led M23 rebels who had seized swathes of North Kivu, with the support of Rwanda, according to U.N. experts.
The prospects of a quick operation against the FDLR are complicated by the rugged terrain the rebels occupy and their past history of striking civilians in revenge when attacked.