The Democratic Republic of Congo army and United Nations peacekeepers have begun a five-day operation to flush out Rwandan rebels from a national park.
Rwanda has twice invaded DR Congo to flush out the rebels
Some 2,000 Congolese soldiers backed up by 500 UN troops and attack helicopters have moved into the vast mountainous Virunga park on the border with Rwanda.
The Rwandans fled to the park after the 1994 genocide and are believed to have devastated the area's wildlife.
Their presence in DR Congo has led to years of conflict in the region.
A UN spokesman said that five rebel camps had been destroyed and 15 fighters had surrendered without a single shot being fired.
There are thought to be some 15,000 militiamen in the area.
The UN says its troops will withdraw from the park when the operation ends but the Congolese army will set up bases there to stop the rebels returning.
A Congolese environmental activist welcomed the operation but expressed the fear that the Congolese soldiers would continue to poach animals in the park, as the rebels had done.
The operation was praised by local villages.
"The Rwandans attacked us every day. They stole our sweet potatoes, peanuts and bananas," Semikore Sebagabo, a 44-year old father of six told AP news agency.
"They even took our women."
Rwanda has twice invaded its much larger neighbour, claiming to be trying to deal with the Rwanda rebels.
Under a 2002 peace deal, most warring parties joined the government and foreign troops withdrew after a five-year civil war in which some three million people died.
But Rwanda continued to threaten to return unless the rebels were disarmed.
In July, the UN mission in DR Congo, Monuc, started to take a tougher line against various militia groups across the lawless east.
Rwandan officials, however, say the UN sweeps may make little difference because they rebels know about them long in advance.
"What these people [UN] do is to go and tell the rebels to vacate a particular area and when they go [out of the park], the rebels return. That does not make sense," Rwanda's envoy to the Great Lakes, Richard Sezibera told the Reuters news agency.