Afghan farmers now planting opium poppies will probably reap a harvest comparable to this year's record crop, in part because insurgents control wide swaths of the south, preventing effective counter-narcotics work, officials said Thursday.

Planting is under way in southern regions responsible for the bulk of the estimated 6,100 tons of Afghan opium produced in the 2005-06 growing season. Anti-drug officials say that despite anti-cultivation campaigns, they foresee little improvement by harvest time next spring.

A senior U.S. official said the new poppy crop probably will be similar to the one planted a year ago, "maybe a little under — we were so high last year." He spoke on condition of anonymity because he is not authorized to speak on the record.

Drug production has skyrocketed since a U.S.-led offensive toppled the Taliban regime five years ago for giving refuge to Usama bin Laden and Al Qaeda camps. Last spring's poppy harvest accounted for 92 percent of the global opium supply and was enough to make 610 tons of heroin — more than all the world's addicts consume in a year.

Police and government officials are deeply implicated in the trade, which adds to the corruption and lawlessness threatening Afghanistan's fledgling democracy. Taliban militiamen had all but eradicated opium cultivation by 2000 but now profit from it, protecting poppy farmers.

Click here to go to FOXNews.com's Afghanistan Center.

Deteriorating security in the countryside makes it difficult to monitor how much poppy has been planted, the U.S. official said. Taliban-led militants have increased attacks this year, particularly in Afghanistan's southern opium heartland.

Gen. Khodaidad, a deputy minister in Afghanistan's Ministry of Counter-Narcotics, said some provincial governors and police chiefs have been doing effective anti-drug work.

"But unfortunately, in some provinces, especially in the south and southwest, we haven't been doing as well," said Khodaidad, who like many Afghans uses one name. "The reason is very clear — fighting. Some of the districts are under the influence of the Taliban or al-Qaida."

Khodaidad said he hoped for a successful anti-cultivation campaign this fall followed by an eradication campaign in the new year, but he said he couldn't promise a reduction in the harvest. "I can tell you there will be no increase," he said.

The United Nations' anti-drug chief said recently that proceeds from Afghan opium production are being used to finance terrorist groups. The U.S. official said the country's drug trade was a $3.1 billion business this year and it doesn't "take much of that to fund terrorism."

Seeking to counter corruption that hinders anti-drug efforts, the U.S. Drug Enforcement Agency is training special units of Afghan policemen who must pass polygraph exams and investigations of their backgrounds, Karen P. Tandy, the DEA administrator, said during a visit Sunday.

"DEA is very accustomed to working in countries where corruption is rampant," she said. "We have a method that has been extremely successful. ... You have patriots in every country who care about the future of their country, and that is no less true here in Afghanistan."

Khodaidad said President Hamid Karzai has warned government officials they will be removed if they help drug trafficking. He said a district chief and an administrator from the same district in Badakhshan, a remote and rugged northern province favored by drug producers, were recently fired.

The U.S. official said if there is no reduction in the opium harvest this year, Afghanistan would come under strong U.S. pressure to start spraying poppy fields with herbicide, an idea that Afghans, including Karzai, deeply oppose because of fears the chemicals could harm people.