The pressure group said the damage was being done in Virunga National Park, located in the Democratic Republic of Congo (DRC), near the borders with Rwanda and Uganda.

"What is happening in Virunga is a disaster," said Marc Languy, coordinator of WWF's programme in the region.

Since April there has been a large influx of labourers from the DRC and Uganda who have begun clearing large swathes of the forest -- up to 1500 hectares (3,700 acres) -- to create agricultural and grazing areas, according to WWF.

"Several thousand people moved in to the area to farm illegally in Virunga, with support from local influential individuals who sold plots of land within the park," the group said in a statement.

The park is home to more than one half of the approximately 700 surviving mountain gorillas, currently one of the most endangered species in the world, according to WWF.

A survey carried out in January revealed that the gorilla population in Virunga was gradually recovering. It showed a 17-percent increase in the number of animals compared to 1989.

The figures came from the first comprehensive survey of the animals since the devastating conflicts that shook the region in the 1990s.

"Loss of habitat is however the worst threat to this species," said Languy.

"It is also a loss for the local communities as the forest provides many ecological and economical services to the neighbouring population" he said.

TERRA.WIRE