The Presidents of Uganda and Rwanda are "on the verge of becoming the godfathers" of an illegal network plundering gold, diamonds and a valuable ore, coltan, from war-torn Congo, according to a UN report.
The report calls for a restricted trade embargo against the central African nations.
A five-member panel found that President Yoweri Museveni of Uganda and President Paul Kagame of Rwanda, "the main sponsors of the three-year rebel war", had "indirectly given criminal cartels a unique opportunity" to exploit the treasure trove of mineral wealth in occupied east Congo.
They are being assisted by the Belgian national airline, Sabena, and other European companies, the report said.
Regional analysts, however, have criticised the report as "unbalanced", saying it ignored similar crimes being committed by government allies Zimbabwe, Angola and Namibia in southern and western Congo.
"What about Robert Mugabe? He's doing exactly the same thing," Hannelie de Beers, senior researcher with the South Africa-based Institute for Security Services, said. "We have to be careful because this could easily sound like Congolese government propaganda."
The report, commissioned by UN Secretary General Kofi Annan, said the Congo conflict "has become mainly about access, control and trade of five key mineral resources: coltan, diamonds, copper, cobalt and gold".
It focused on the exploitation of coltan, a rare ore used to make high-tech devices, such as mobile phones and satellites, in areas occupied by the Rwandan-supported RCD rebels. Low supplies resulted in a shortage of Sony Playstation game consoles in Europe and the US last Christmas.
The illegally mined ore is bought by 20 European companies, mostly Belgian, Dutch and German, and earns the rebels at least $1 million per month.
Sabena Cargo is identified as one of the "key companies in this chain of exploitation and continuation of war" for its role in flying the precious ore from Rwanda to Brussels.
In addition, Uganda, Rwanda and Burundi have been exporting large quantities of diamonds and gold since the war started in 1998, though their own deposits are negligible.
Senior army officers, government figures and shady businessmen have all got rich from the illegal trade, the report said. President Museveni's brother Gen Salim Saleh and Gen James Kazini are singled out.
The report said it could not prove that President Museveni or President Kagame were directly involved in the plunder.
However, it does question whether the large Western aid both leaders receive helps to fund their war efforts. Uganda is one of Ireland's six priority beneficiaries of foreign aid.
The panel called for a ban on the trade of diamonds, gold, timber, coltan and other rare minerals to and from Rwanda, Uganda and Burundi.
But such measures would be "one-sided", said Mr Francois Grignon, a senior political analyst with the International Crisis Group. Rwanda started the war to drive out the Hutu militia that committed the 1994 genocide, he said, and "to say that Rwanda is in the Congo only for reasons of greed is a total distortion of reality," he said.