A former U.S. State Department official charges Afghanistan's drug trade is being protected by the country's top officials.

Thomas Schweich wrote in an article posted on The New York Times website Thursday, that U.S. efforts to eliminate Afghanistan's poppy crops have been repeatedly thwarted by Afghan President Hamid Karzai.

Schweich left his post as coordinator for Counter Narcotics and Justice Reform in Afghanistan last month.

He alleges that while Taliban militants use the opium trade to finance their insurgency, Mr. Karzai and his supporters have also used the drug trade to get rich.  

He writes that the Afghan president is using the drug trade to secure his political standing in order to win reelection in 2009.

No U.S. or Afghan officials were immediately available for comment.

According to the United Nations and the U.S., Afghan farmers produce 93 percent of the world's opium poppies.

A report by the U.N. Office on Drugs and Crime earlier this year predicted the 2008 Afghan poppy crop would be large, but smaller than it was in 2007.

Schweich also claims President Karzai was able to undermine U.S. attempts to destroy poppy crops by citing divisions among U.S. officials.

He writes that some U.S. military commanders obstructed counter-narcotic efforts, arguing that fighting the drug trade should not be part of the military's mission.

Some information for this report was provided by AP.