BOGOTA (Reuters) – Colombian guerrillas have entered into “an unholy alliance” with Islamic extremists who are helping the Marxist rebels smuggle cocaine through Africa on its way to European consumers, a US official told Reuters.

Interdiction efforts have made it more difficult to send cocaine straight from Colombia and other Andean producer nations to the United States and Europe.

So criminal organizations including the Revolutionary Armed Forces of Colombia, or FARC, are going through Africa to access the European market. And they are doing it with the help of al Qaeda and other groups branded terrorists by Washington, according to the US Drug Enforcement Administration.

“In the mid to late 1990s when the Europeans became better at maritime interdiction, off the coasts of Portugal and Spain for example, traffickers started moving their routes southward. So the next progression was to Western Africa,” said Jay Bergman, DEA director for the Andean region of South America.

Three West African men accused of ties to al Qaeda were extradited to New York in December on drug trafficking and terrorism charges.

It was the first time US authorities established a link suggesting al Qaeda is funding itself in part by providing security for drug smugglers in West Africa.

“As suggested by the recent arrest of three alleged al Qaeda operatives, the expansion of cocaine trafficking through West Africa has provided the venue for an unholy alliance between South American narco-terrorists and Islamic extremists,” Bergman said in an interview over the weekend.

To reach the US market, Colombian smugglers are meanwhile being driven to use disposable, fibreglass submarines. The homemade craft are constructed in the mangroves of Colombia’s Pacific coast, used to carry drugs to Mexico for transshipment to the United States, then sunk.

All big Colombian trafficking groups, including the 45-year-old FARC, are using Africa to reach European cocaine consumers while Mexican cartels import chemicals used to make methamphetamine via the same route, Bergman said.

“For trafficking organizations to survive, they first and foremost have to be flexible and make adjustments quickly to law enforcement efforts,” he added.

“West Africa is that current alternative.”

When sea interdictions stepped up, traffickers started using planes to get cocaine to Africa. Most flights appear to take off from Venezuela, which shares a border with Colombia.

“All of the aircraft seizures that have been made in West Africa, and we’ve made about a half a dozen of them, had departed from Venezuela. If you look at the range and refueling requirements, that’s the place you have to fly from,” he said.

“Geography is the key reason why Venezuela has become a springboard location,” Bergman added.

Venezuela’s fiery left-wing President Hugo Chavez says the United States and Colombia are using anti-drug operations as a cover for a planned invasion of his oil-rich country. Washington and Bogota dismiss the allegation.

The West African drug trade meanwhile threatens to further destabilize countries such as Guinea Bissau, where traffickers have been implicated in the killing of a president.

To clamp down on the Colombia-to-Africa cocaine route the DEA is focusing on improving its intelligence rather than relying on costly patrols over the Atlantic.

“It is much cheaper to have a DEA agent operating in West Africa with sources of information that can pinpoint the time that a plane is leaving or the route that a ship is taking and the name of that ship, than it is to set up a gauntlet of multinational frigates and surveillance planes,” Bergman said.