Afghan counter-narcotics officials said Wednesday that they uncovered 260 tons of hashish hidden in 6-foot-deep trenches in southern Afghanistan in what one official said appears to be the largest-ever drug bust. The hashish, found in the southern province of Kandahar on Monday, was worth more than $400 million and would have netted the Taliban about $14 million in profits, NATO's International Security Assistance Force said. The hashish weighed as much as 30 double-decker London buses, ISAF said. The drugs were burned on site. "The Afghan National Police Special Task Force has made a huge step forward in proving its capability in curbing the tide of illegal drug trade in this country," U.S. Gen. David McKiernan, the commander of ISAF, said in a statement. "With this single find, they have seriously crippled the Taliban's ability to purchase weapons that threaten the safety and security of the Afghan people and the region." Garrison Courtney, the spokesman for the US Drug Enforcement Agency, said he thought the drug bust was the world's largest in terms of weight. He called the takedown "pretty huge." "I can't think of any other time I've ever heard of that large of an amount in one hit," he said. Afghanistan's biggest drug problem is not hashish but opium. The country produced 9,000 tons last year, enough to make over 880 tons of heroin - 93 percent of the world's supply. But officials have increased warnings that farmers who no longer grow opium poppies because of successful eradication programs have turned their fields to cannabis, the plant used to produce hashish and marijuana, giving the country a second drug problem to contend with. Deputy Interior Minister Lt. Gen. Abdul Hadi Khalid, who announced the hashish bust Wednesday, said three men were arrested in the raid. He credited the international community for helping to train the Afghan special narcotics forces. He said that 21 of the country's 36 provinces are now opium-free, but that efforts to eradicate in Kandahar, Helmand, Farah and Uruzgan provinces did not go well this year because of continuing violence there. Forty-three members of the country's counter-narcotics police were killed during eradication operations this spring, he said. In a separate recent counter-narcotics operation in nearby Helmand province, the Interior Ministry said police seized 11,250 pounds of opium and arrested 13 drug dealers.