The hunt for minerals has fuelled the conflict
The United Nations' Security Council is due to meet to consider a report on the impact the plundering of resources has had on the conflict in the Democratic Republic of Congo.
The final document from a specially-commissioned panel of experts looks at the role played by international mining companies in the country.
It draws a direct link between their activities and the funding of armed Congolese groups.
As in previous documents, it states that money from companies involved in illegally extracting minerals and resources from DR Congo has inevitably fuelled fighting by providing funds to armed groups.
This last report explains how the panel of experts met many of the companies involved and attempted to explain how their business practises were exacerbating the impact of the war on the Congolese people.
The companies were urged to raise their corporate behaviour in conflict areas and at the very least to abide by the same rules they followed at home.
Some listened to this advice and changed their practices in DR Congo, but others did not, the report says.
The report names 18 companies, including some well known international operators, like the diamond giant De Beers, which it says either rejected suggestions that their activities in the DR Congo are questionable or refused to accept that they have a responsibility to avoid providing support even inadvertently to rebel groups there.
But a spokesman for De Beers, Andrew Bone, said his company, which was named in a previous UN report, has in fact been trying to stop the trade in conflict diamonds.
Human rights campaigners want the UN to probe the exploitation of Congo's natural resources
"De Beers is the only company that was on the list - on the original list in fact - that had called for sanctions to be applied to those diamond areas within the DR Congo that were feeding rebels there and the conflict," he told the BBC.
"The point here is that the panel has said that three companies that are clients of De Beers were purchasing diamonds from countries that they perceived to have been contributing to the destabilisation in that country." he said.
According to the BBC's Greg Barrow in New York, the UN panel has suggested further investigations may be necessary into the activities of the companies it has named.
But UN diplomats say it is unlikely they will face prosecution.
This is not the first time the UN panel has drawn a direct link between the mining companies and the funding of armed groups.
It urges businesses to raise their corporate behaviour in conflict areas - or at the very least to abide by the same rules they follow at home.
Meanwhile, the UN says it has received an assurance that its peacekeeping troops in DR Congo will have full access to the east of the country.
The assurance, which was given in a letter from the government of North Kivu province, comes after repeated allegations that Rwandan forces were still operating in the east.
Fighters from the Rwandan-backed Congolese Rally for Democracy prevented UN troops from entering a military camp in North Kivu.