The United Nations has been accused of covering up allegations that its peacekeepers traded gold, ivory and arms with violent rebel groups in the Democratic Republic of Congo.

Confidential sources told the the BBC that Pakistani and Indian troops were implicated in arms deals.

It is the latest scandal to hit the UN’s mission to the DRC, where soldiers and officials have been accused of repeated sexual misconduct.

The UN said that it investigated the accusations last year but could find no evidence that troops had supplied arms to militias.

But the 18-month investigation by the BBC Panorama programme concluded that such deals had taken place, and that UN staff had been told not to pursue their investigations for fear of upsetting Pakistan - the biggest contributor of peacekeepers.

At the time, Jean-Marie Guehenno, the head of the UN’s peacekeeping division, said: "The investigation has found no evidence of gun smuggling. But it has identified an individual who seemed to have facilitated gold smuggling.

"We have shared the report with the concerned troop-contributing country and I am confident they will take the required action. And this issue is closed."

The United Nations Mission in the Congo, with 17,000 troops, is the biggest in the world. It was deployed eight years ago and has brought a measure of stability to a country ravaged by civil war.

But armed groups continue to rape, murder and loot their way through large parts of the eastern DRC, where thousands of civilians are still being uprooted.

At the same time the UN’s peacekeeping mission, known as Monuc, has been implicated in a series of sex scandals.

An investigation by The Times found that at least two UN officials had to leave the country after getting local women pregnant.Sixty-six peacekeepers were repatriated and six civilian staff suspended when charges of misconduct came to light.

The latest allegations involve Pakistani peacekeepers in the eastern town of Mongbwalu, who are accused of receiving gold from the Front des Nationalistes et Intégrationnistes (FNI) militia in return for providing them with weapons to guard mines.

Indian soldiers around the town of Goma are also accused of direct dealings with Hutu militiamen responsible for the Rwandan genocide. They bought gold and drugs from the Forces Démocratiques de la Libération du Rwanda (FDLR) - made up of the remnants of the Interahamwe - and flew a helicopter into Virunga national park, where they swapped ammunition for ivory.

Evidence included interviews with two FNI commanders in their prison cells in Kinshasa, who confirmed the involvement of Pakistani soldiers.

The head of Monuc, Alan Doss, dismissed their evidence as untrustworthy. "Militia leaders are militia leaders," he said. "They always have their interests, if you will. All I can say is this investigation didn’t confirm that."

Times Recommends

• How the fall of the Wall freed Nelson Mandela
• Iguacu, the world’s most spectacular waterfall
• How Harrods helped Burmese cats return