US defense contractors are funding insurgents in Afghanistan, to the tune of tens of millions of dollars, according to a report in The Nation published Thursday.

The report, by veteran investigative correspondent Aram Roston, asserts that US military contractors charged with assisting US forces in Afghanistan are actually funding the groups killing American soldiers. Roston describes a protection racket similar to that of the mafia, in which contractors pay the Taliban "protection money" not to attack them.

"In this grotesque carnival, the US military's contractors are forced to pay suspected insurgents to protect American supply routes," Roston writes. "It is an accepted fact of the military logistics operation in Afghanistan that the US government funds the very forces American troops are fighting. And it is a deadly irony, because these funds add up to a huge amount of money for the Taliban.

"It's a big part of their income," a top Afghan government security official purportedly told told The Nation.

Added an American defense executive, "The Army is basically paying the Taliban not to shoot at them. It is Department of Defense money."

US officials estimate that as much as ten percent of taxpayer money doled out to private contractors ends up in insurgents' hands. By a quick accounting, this amounts to tens of millions of dollars.

Mike Hanna, a manager for Afghan American Army Services, a trucking firm, told Roston that paying off the Taliban was a necessary evil.

"We're basically being extorted," Hanna is quoted as saying. "Where you don't pay, you're going to get attacked. We just have our field guys go down there, and they pay off who they need to.

"Moving ten trucks, it is probably $800 per truck to move through an area," he added. "It's based on the number of trucks and what you're carrying. If you have fuel trucks, they are going to charge you more. If you have dry trucks, they're not going to charge you as much. If you are carrying MRAPs or Humvees, they are going to charge you more."

"If you tell me not to pay these insurgents in this area," he continued, "the chances of my trucks getting attacked increase exponentially."

Roston says paying the Taliban for protection is an issue of pragmatism.

"The heart of the matter," he writes, "is that insurgents are getting paid for safe passage because there are few other ways to bring goods to the combat outposts and forward operating bases where soldiers need them. By definition, many outposts are situated in hostile terrain, in the southern parts of Afghanistan. The security firms don't really protect convoys of American military goods here, because they simply can't; they need the Taliban's cooperation."

He notes that contractors, by regulation, are banned from carrying any weapons more serious than a rifle. This means they're far outmatched when contending with insurgents that have rocket-propelled grenades.

The US military shells out huge sums of money to supply troops in remote Afghan areas, even outside the protection racket.

A recent estimate from the Pentagon found that the government spends some $400 a gallon for gasoline in Afghanistan when all transport costs are included.

Afghanistan is landlocked, meaning that fuel must be transported in ways that stretch the limits of economic reason.

Because the country has no seaports, fuel is shipped to Karachi, in Pakistan, then carried across land by commercial trucks through Afghanistan. For remote bases, gasoline is sometimes transported by air.

Some fuel is even transported in "bladders" attached to the belly of helicopters.

The Nation report was underwritten by the Nation Institute, a nonprofit that funds investigative journalism.