American officials have no strategy for fighting corruption in one of the most corrupt countries in the world despite spending $96 billion in a dozen years on Afghan reconstruction, according to a government watchdog.

"We found that the U.S. anti-corruption activities in Afghanistan are not guided by a comprehensive U.S. strategy or related guidance that defines clear goals and objectives for U.S efforts to strengthen the Afghan government’s capability to combat corruption and increase accountability," said John Sopko, special inspector general for Afghan reconstruction, in a report made public Wednesday.

Sopko said persistent corruption in Afghanistan's government "raises the risk that reconstruction funds will be misused or wasted, reduces popular support for the Afghan government, hampers economic growth and governmental performance, and reduces international support for the entire reconstruction effort."

Despite claiming one of its top priorities is strengthening the Afghan government's ability to fight corruption, Sopko said the lead U.S. agency responsible for that goal lacks a strategy of its own.

The U.S. Department of State drafted an anti-corruption strategy in 2010, but then-Secretary of State Hillary Clinton never implemented it, and no comprehensive strategy or plan currently exists, according to Sopko.

The two international agreements used by the State Department to guide its anti-corruption efforts, the Tokyo Mutual Accountability Framework and the U.S. Civil-Military Strategic Framework for Afghanistan, lack metrics to measure progress in reducing corruption.

Corruption in Afghanistan has wasted billions of U.S. tax dollars and military supplies.

"Widespread corruption in Afghanistan is a significant problem and remains a threat to the success of reconstruction and assistance programs," Sopko said in Wednesday's report. "In 2012, Transparency International ranked Afghanistan in a tie with Somalia and North Korea as the most corrupt country in the world."

A SIGAR spokesman added that the IG "has examined and reported on projects, programs, issues, etc., with an estimated total value in excess of $10.6 billion. Of that, SIGAR has identified $6.7 billion that we consider to be at risk of waste, fraud and abuse."

In August, SIGAR and the Department of Justice froze the bank account of an Afghan trucker who allegedly bribed his way into thousands of overpriced contracts to transport goods for the U.S. military.

Truckers running an ongoing fuel-theft scheme at Forward Operating Base Salerno in Khost province stole almost 53,000 gallons of fuel per month until SIGAR helped shut them down in December 2012.

More than 60 Afghan fuel truck truckers were stealing between 600 and 2,400 gallons of fuel from their deliveries, which they could sell on the black market. The drivers were barred from U.S. and NATO installations in Afghanistan, and SIGAR works with the Afghan attorney general's office to prosecute them locally.