KABUL – U.S. Marines and Afghan forces have found and destroyed hundreds of tons of poppy seeds, opium and heroin in southern Afghanistan this month in raids that a top American official said show the new U.S. counter narcotics strategy in Afghanistan is working.

U.S. and NATO troops are attacking drug warehouses in Afghanistan for the first time this year, a new strategy to counter the country’s booming opium poppy and heroin trade. NATO defense ministers approved the targeted drug raids late last year, saying the link between Taliban insurgents and drug barons was clear.

U.N. officials say Taliban fighters reap hundreds of millions of dollars from the drug trade each year, profits used to fund the insurgency.

The U.S. announced last month it would no longer support the destruction of individual farmers’ poppy plants, and instead would increase attacks on drug warehouses controlled by powerful drug lords – a wholesale change in strategy.

U.S. Marines, British troops and Afghan forces supported by the U.S. Drug Enforcement Administration have increasingly targeted drug warehouses in Helmand and Kandahar provinces – the largest opium poppy growing region in the world.

Richard Holbrooke, President Barack Obama’s envoy for Afghanistan and Pakistan, said early evidence indicated the new strategy was working.

“This administration set out to reverse the counter narcotics program by de-emphasizing crop eradication and emphasizing interdiction,” Holbrooke told The Associated Press on Saturday. “The forces in the south are actually making that a reality. It’s a historic change if it’s successful, and the first indications were very, very promising.”

Seizures made this summer illustrate the huge quantities of drugs the military can destroy.

Marines in Helmand working alongside DEA-mentored Afghan police seized 297 tons of poppy seeds, 77 pounds (35 kilograms) of heroin and 300 pounds (135 kilograms) of opium in raids in mid-July. Some 1,200 pounds (550 kilograms) of hashish and 4,225 gallons (16,000 liters) of chemicals used to convert opium to heroin were also seized.

“This wasn’t an accident. This was planned interdiction,” Holbrooke said.

Bomb-making materials, rocket-propelled grenades and AK-47s were also seized, underscoring what the U.S. Embassy said was “the connection between drug trafficking and the insurgency.”