Just a few weeks ago, rangers and militiamen were engaging in gunfights in Africa's oldest national park. Cannons boomed as Congolese army troops shelled rebels.

That fighting in Virunga National Park, where virtually every rebellion in eastern Congo in the past 30 years has started, died down in August but the park still is facing threats from a new rebel group and from a controversial decision to open it to oil exploration.

The park, created under Belgian rule in 1925, encompasses the Rwenzori mountains' snowfields and glacier at over 5,000 meters (16,400 feet), seven volcanoes, a lake filled with hippopotamuses, marshlands and rolling plains roamed by elephants, buffalo, lions, leopards. Siberian birds winter in the park, among 700 species whose squawks and squeaks provide a wildlife musical interlude broken by the shrieks of baboons. The park boasts more than 200 species of mammals including the giraffe-like okapi found only in Congo. It is the only place on Earth where one can see all three African great apes, among its 22 primates.

The number of rangers protecting Virunga is down from 1,000 to 271, including 48 recruits trained by retired Belgian Special Forces. There are also 200 Congolese government soldiers here.

In July, there was hand-to-hand combat at the park headquarters when rebels attacked. Artillery fire ended in August with a stalemate in which rebel forces control a neighboring army barracks and occupy parts of the park. The fighting forced authorities to close the park and a newly built luxury lodge with 12 bungalows constructed from lava rock. From the number of Italians, Australians, Japanese and Chinese who visited after the lodge opened in January, Emmanuel de Merode, the park's director and chief warden, had hoped that proceeds from the luxury lodge would help make Virunga economically self-sufficient.

But now, instead of well-heeled tourists, a quarter-million people displaced by fighting in eastern Congo are camped along the park boundary and are cutting down trees for cooking fires. And conservationists fear oil exploration may irrevocably harm the park.

President Joseph Kabila has signed decrees authorizing oil concessions that cover about 85 percent of Virunga's 7,800 square kilometers (3,000 sq. miles), nearly the size of Yellowstone National Park in America. French oil company Total has pledged not to exploit the 30 percent of its concession that falls in Virunga but London-registered SOCO International has said it will go ahead with exploration of its concession, with 58 percent in the park.

SOCO points to an exemption under the conservation law and says its exploration is "scientific research." It notes there are other exemptions, such as for the 40,000 fishermen who live off the park's Lake Edward, where SOCO says its exploration would not harm animals or fish. The company has promised not to explore in the mountain gorilla habitat, around Virunga's volcanoes or in the park's equatorial rainforest.

Britain's Foreign Office, whose mandate includes support for British companies operating abroad, took the unusual step last month of issuing a statement to say "The United Kingdom opposes oil exploration within Virunga National Park, a World Heritage site listed by UNESCO as being 'in danger.' We have informed SOCO and urge the Government of DR Congo to fully respect the international conventions to which it is a signatory."

SOCO has denied accusations by Virunga park management that the company is willing to pay money to secure support from local politicians, military personnel and civil servants. At one point, park officials denied SOKO staff entrance to the preserve.

"SOCO vigorously denies any allegations of impropriety ... (and) does not permit the giving or receiving of bribes," the company said.

The U.N. World Heritage committee says "oil and mining exploration and exploitation are specifically prohibited in the protected areas of the Democratic Republic of Congo," citing its nature conservation law of 1969 and the mining code of 2002. The debate over Virunga has set Congo's environment and mining officials at loggerheads and new battle lines could be drawing up in the park with such a troubled history.

"Our role as government wildlife officers is to uphold the laws that protect the forests and the wildlife of Congo," said de Merode.