The majority of small arms and munitions sent to Syrian rebels by Arab nations are falling into the hands of terror groups operating in the country, according to a U.S. review of those efforts.

Classified analysis of the Syrian civil war by U.S. officials found weapons caches sent by countries such as Saudi Arabia and other Gulf states are going to hardline Islamic terror groups fighting alongside rebel forces in the country.

“The opposition groups that are receiving the most of the lethal aid are exactly the ones we don’t want to have it,” a U.S. official familiar with the classified findings told The New York Times on Monday.

The report backs up the White House's main argument against directly supplying rebel forces looking to overthrow Syrian president Bashar Assad with U.S. weaponry.

The administration's concern is those weapons could end up being used against American targets across the globe by the radical Islamic factions fighting shoulder to shoulder with ant-Assad forces.