A special anti-narcotics task force has raided drug laboratories in eastern Afghanistan (search), seizing more than 15 tons of opium as part of President Hamid Karzai's (search) crackdown on what he calls the country's biggest threat, officials said Thursday.

That amount of opium (search), one of the largest confiscations in recent years, could have been refined into about 11/2 tons of heroin. U.N. surveys estimate Afghanistan accounted for three-quarters of the world's opium last year.

The raids took place Wednesday in Nangarhar province's Achin district, an Interior Ministry statement said, adding that Afghan Special Narcotics Force agents also destroyed 24 opium presses that are used to refine the drug. They also seized three tons of chemicals used to process opium into heroin and five AK-47 assault rifles.

But no arrests were made as the labs' operators apparently fled just before the operation began.

"This is a legitimate action ... to destroy the drug economy in Afghanistan," Interior Minister Ali Jalali said. "This operation is a proven example for other growers or traffickers that from now on, the government of Afghanistan is committed to destroying the drug economy."

Another bust last week yielded nearly two tons of opium.

Karzai said in his Dec. 6 inaugural address that the country's booming drug economy — estimated to account for 60 percent of gross domestic product — will be the top priority in his fresh five-year term. He said it is linked to terrorism and called it a bigger threat than the Taliban and Al Qaeda insurgents who mount almost daily attacks in the countryside.

The United Nations has warned that the exploding narcotics industry is turning the impoverished country into a "narco-state."

"Without substantial progress in addressing the sources of insecurity, reconstruction efforts and the establishment of viable state institutions will continue to falter, and the economy may well be subsumed by the illicit drugs industry," U.N. Secretary-General Kofi Annan said earlier this month.

Afghan and British officials preparing a crackdown on Afghanistan's booming illegal narcotics industry have begun training a legal task force for special courts they hope will begin jailing heroin and opium kingpins within months.

A secure court and prison facility is being set up at a notorious prison near Kabul to house the first convicts by the middle of 2005.

Plans are also being laid to punish farmers by destroying opium poppy crops in key growing regions early next year. Meanwhile, hundreds of millions of dollars are earmarked to help them switch to less lucrative but legal crops.