Antonio Maria Costa, on a visit to NATO, which took over command of the 5,300-member International Security Assistance Force in Kabul last month, said Afghanistan had once again become the world's largest producer of opium.

"The military of Enduring Freedom should get involved in the fight against trafficking," he said. "A very major drug game is being played in Afghanistan at the moment."

He said many of the warlords who rule the country outside the capital are taking a cut from drug trafficking proceeds.

"The revenue is big but the risk is small," he said, adding that traffickers knew they currently ran "practically zero" risk of being arrested.

Costa, who heads the UN Office on Drugs and Crime based in Vienna, said the current growth in drug trafficking from Afghanistan was "worrisome."

WAR.WIRE