Washington and Kabul have failed to keep track of hundreds of thousands of weapons provided to Afghanistan, raising the risk that some could end up in the hands of insurgents, a US audit said Monday.

The United States also had delivered more weapons than Afghan forces now needed, partly because Kabul officials had revised their requests over time, the report said.

Since 2004, the American military has delivered more than 747,000 AK-47 rifles, machine guns, grenade launchers and other weapons to Afghan forces worth about $626 million.

But the US and Afghan governments have botched record-keeping for the weapons, with potentially tens of thousands of assault rifles and other arms unaccounted for, according to the findings of the Special Inspector General for Afghanistan Reconstruction.

"Given the Afghan government's limited ability to account for or properly dispose of weapons, there is a real potential for these weapons to fall into the hands of insurgents," the report said.

The US military had problems tracking the weapons before delivery and Kabul authorities had "severe problems" with accounting for the massive flow of arms, it said.

Record-keeping and inventory efforts by Afghan National Security Forces (ANSF) were "poor" and the inspector general's inspections at supply depots revealed missing weapons and other discrepancies, the report said.

In addition, the Afghan army and police had about 112,000 weapons over and above the stated requirements of Afghan commanders, it said.

The excess weapons were partly due to changing requests over time from Kabul but there were no plans to recapture or remove the surplus guns and other arms, the report said.

"Another reason that some weapon types exceed current requirements is the ANSF's desire to obtain new weapons, rather than repairing old ones," it said.

The inspector general warned that the danger of excess weapons likely would be aggravated as Afghan security forces are scaled back in coming years. A tentative plan agreed by NATO allies would reduce the force from 352,000 to roughly 228,500 by 2017.

The audit called for a reconciliation of disparate US records, which currently rely on two separate data bases that are not linked.

The inspector general urged the Pentagon to help the Afghan government carry out a 100 percent inventory check of all small arms supplied to Kabul, and recommended Washington and Kabul draw up a plan to recover excess weapons and curtail deliveries as Afghan troop levels decrease.

The blunt-speaking inspector general, John Sopko, has accused US agencies of dumping billions of dollars on ill-conceived aid projects in Afghanistan.

"We spent too much money, too fast, in too small a country with little oversight," Sopko told AFP in an interview last week.