"If we can find six new species in such a short period it makes you wonder what else is out there," said researcher Andrew Plumptre.

The new species discovered were a bat, a rodent, two shrews and two frogs.

Aid agencies estimate around 4 million Congolese have been killed in fighting or by related hunger and disease since the outbreak of the country's 1998-2003 war, in which six foreign armies joined in fighting over its huge mineral riches.

Despite a 2003 peace deal and the country's first free elections in more than 40 years being held last year, militia fighting continues in parts of the east.

"In spite of the conflict and related degradation in the area, the survey team found that some 1,000 square kilometers have remained intact, from the shores of Lake Tanganyika up to elevations of 2,725 meters above sea level," a statement said.

It said the area had been off limits to scientists since 1960 because of instability. The team also included researchers from the Field Museum in Chicago, the National Centre of Research and Science in Lwiro and the World Wildlife Fund.

The statement said the forest was extremely rich in biodiversity, containing a large number of chimpanzees, buffalo, elephants, leopards and monkeys.

Around 10 percent of the plant samples collected have yet to be identified.

"Given the findings with the vertebrates, it is likely that some of the plants will represent new species as well," said Ben Kirunda of the group's botanical team.

The researchers said they met village leaders who were mostly supportive of making the region a protected area.

"Since few people live there, it would be relatively easy to create a park while supporting the livelihoods of people who live in the landscape," said James Deutsch, director of the Wildlife Conservation Society's Africa Program.

Democratic Republic of the Congo's wildlife, particularly mountain gorillas in the Virunga National Park, was a significant tourist attraction before the 1998-2003 war.