Some 87,000 pieces of weapons given by the Pentagon to Afghan army and police units are unaccountable, U.S. congressional auditors said in a report on Thursday, Xinhua reported.
The missing weapons included rifles, pistols, machine guns, grenade launchers, shotguns and mortars, said the report written by the Government Accountability Office, or GAO, the investigations arm of Congress.
The weapons are among about 240,000 small arms and other sensitive items, including 2,410 highly prized night vision devices that were given to Afghan security forces being trained by the U.S. military.
The report also said the Pentagon also failed to keep serial numbers or other records on about 135,000 weapons donated by allies and handed over to Afghan security forces.
The U.S. effort to train and equip Afghan security forces so far has cost 16.5 billion U.S. dollars, and will cost another 5.7 billion dollars this year, according to U.S. officials.
The GAO said the security lapses were due to "a lack of clear direction" from the Defense Department "and staffing shortages" at the headquarters of the U.S. Combined Security Transition Command- Afghanistan, which is responsible for training and equipping Afghan security forces.
But a Pentagon spokesman, Bryan Whitman, told reporters that " the record will show that our performance on this has improved over time."