U.S. and international forces can't keep track of hundreds of millions of dollars in vehicle parts purchased for the Afghan National Army with American funds — because no one is keeping inventory.

That means, according to John F. Sopko, the military's "current process for managing vehicle spare parts purchases leaves U.S.-purchased equipment and funds vulnerable to waste, fraud, and abuse."

Sopko is the Special Inspector General for Afghanistan Reconstruction.

The Combined Security Transition Command-Afghanistan, or CSTC-A, is the multinational organization that trains and equips the Afghan National Army.

The CSTC-A has spent $370 million on vehicle parts for ANA since 2004, much of which can't be accounted for because neither has accurate records of what's been purchased, distributed and used, Sopko said in a report released Wednesday.

Extra parts can sit in overflow lots for more than a year waiting for ANA to do its inventory, leaving the parts vulnerable to fraud and wasting U.S. dollars, the report said.

CSTC-A relies on ANA to keep inventory records of its spare parts, and to base its orders on these records. But ANA's poor and inconsistent record-keeping means it has no way to accurately judge how many parts are actually needed.

ANA isn't the only one to blame. In October 2012, CSTC-A could not account for approximately $230 million worth of spare parts, and subsequently ordered more than $138 million more in spare parts to replace the ones it had lost, without knowing what ANA had in storage.

"With inventory sitting at depots unrecorded in the ANA system, CSTC-A likely ordered duplicate parts," Sopko wrote.

After a June 2013 meeting with SIGAR, CSTC-A said it would begin sending spare parts containers to a U.S. transfer point before transferring them to the ANA, to improve accountability for the inventory. CSTC-A is also working on recovering spare parts until the ANA can conduct an accurate inventory.

Other plans for future funds are more problematic, Sopko said. CSTC-A officials told SIGAR they plan to give ANA control of parts purchasing with a limited defense grant, which would be based on a list of prioritized needs.

The officials said the limited amount of funding would force ANA to determine its needs before ordering.

"Giving the ANA more responsibility for tracking and shipping vehicle spare parts raises concerns, as the ANA is not yet consistently using or updating its inventory to track what is currently in stock, what stock has been ordered by ANA units, and when and where stocks are supposed to arrive," Sopko said.

The report comes just a few weeks after a report on CSTC-A's poor oversight of fuel purchases for the Afghan National Police. SIGAR warned that CSTC-A's plans to give the Afghan National Police direct control of its fuel purchases could put even more U.S. money at risk.

Read the full report here.