WASHINGTON — The United States said Thursday it has contributed $1 million to a United Nations program to help probe, arrest and prosecute drug traffickers working in Afghanistan and Central Asia.

The United States gave the funds Wednesday in Vienna to the UN Office on Drugs and Crime's (UNODC) Regional Program for Promoting Counternarcotics Efforts in Afghanistan and Neighboring Countries, according to the State Department.

The funds are aimed at "promoting enhanced techniques for the investigation, arrest, and successful prosecution of significant drug traffickers operating in Afghanistan and Central Asia," the agency said in a statement.

The contribution is also designed to disrupt their trafficking networks.

The UNODC regional program, the State Department said, is "expected to complement" US efforts in the region to send more US Drug Enforcement Administration officers to Central Asia to work with their regional counterparts.

An annual State Department report said last week that the Afghan government has made progress in the last year in fighting drugs trafficking and cultivation, but added that the "gains remain fragile."

Afghanistan grows about 90 percent of the world's opium.