The new conflict in the Democratic Republic of Congo has forced dozens of rangers to flee Africa's oldest national park, leaving hundreds of threatened mountain gorillas at the mercy of rebel fighters and poachers.

Wildlife officers escaped into the forest when fighters loyal to renegade general Laurent Nkunda occupied part of the park as they launched their march on Goma, the main city in the east of DR Congo.

Set up in 1925, Virunga covers some 7,800 square kilometres. Its varied terrain includes two of Africa's most active volcanoes, swamps and snow-capped mountains.

It is also home to more than half of the world's 700 remaining mountain gorillas as well as 20,000 hippopotamus, according to the World Wildlife Fund.

UNESCO named Virunga a World Heritage site in 1979 and placed it on the organisation's endangered list in 1994 when a first civil war broke out in the country.

DR Congo's Environment Minister Jose Endundo Mononge said that the fighting between the army and Nkunda's rebels poses a great threat to the park and would hit tourism income, while opening up worrying opportunities for poachers.

"In just 2007, we recorded the slaughter of 15 mountain gorillas ... and more than 20,000 antelopes," he told a press conference in Kinshasa.

Park rangers told how they fled Virunga on October 26 after Nkunda's forces moved in as part of their campaign to take over Nord-Kivu province.

"We were at our posts when we heard an exchange of gunfire between the rebels and the army. At around 6:30am, the gunshots got closer so we fled into the forest," said Desire, a 31-year-old ranger.

Benjamin, a ranger at Kalengera, 60 kilometres north of Goma, told how his father was killed by rebels and how he has no news of his wife and five children. Benjamin spent four days hiding in the forest before arriving in Goma a week ago.

"There are a lot of people in the forest. Not just park rangers, but families as well. Some have died there; from exhaustion, lack of food and water," he said.

"The rebels came and started killing people. My father lost his life over there. I was hidden in a house with friends. We fled into the forest while my family stayed in the village and they are still there.

"They said that my father has been buried but I wasn't there to see it."

Desire and 52 others headed for the town of Rumangabo as Nkunda's National Congress for the Defence of the People (CNDP) took territory around Goma, 50 kilometres to the south of the park.

Desire and 180 of the park's 680 rangers are now hiding in a small camp set up on the outskirts of Goma by the Congolese National Park Authorities.

"We spent three days and two nights in the forest," Desire explained. "We survived by eating fruit, leaves and drinking water in the volcanic rocks."

Jules, the 35-year-old head of an anti-poaching unit, took cover at his grandfather's house in Goma after having taken a more dangerous route to the north of the city - straight through the area where rebels and pro-government militia had clashed.

"We fled and spent two days in the forest. We ate bean leaves. We had no water. It did rain but we had no way of storing it," he said.

"We left our uniforms and we headed back towards Kiwanja. But the Mai-Mai (a pro-government militia) had already started an attack against the rebels."

Jules was eventually escorted back to Goma by a UN convoy.

- AFP