Dec. 14 (UPI) -- Sophisticated weapons the U.S. military secretly provided to Syrian rebels ended up with the Islamic State, a study said Thursday.
Conflict Armament Research, a British-based organization, examined 40,000 weapons and other items recovered from the Islamic State from July 2014 to last month -- time which the U.S.-led coalition removed militants from Iraq and Syria.
The 201-page report concludes that "international weapon supplies to factions in the Syrian conflict have significantly augmented the quantity and quality of weapons available to IS forces -- in numbers far beyond those that would have been available to group through battlefield capture alone."
The report said 90 percent of the weapons and ammunition studied originated in China, Russia and Eastern Europe, but some were provided by the United States and Saudi Arabia to Syrian opposition forces opposed to President Bashar al-Assad
"These findings support widespread assumptions that the group initially captured much of its military materiel from Iraqi and Syrian government forces," the report said.
According to the report, the arms included anti-tank weapons from the United States that the Islamic State acquired less than two months after leaving the factory. Other items affected were ammunition and chemical components used to make explosive devices.
The U.S. government uses private companies to make the weapons because most militants use AK-47s and rocket-propelled grenades from former Soviet bloc countries or China that aren't compatible with most U.S.-manufactured ammunition and other supplies.
The report didn't determine a breakdown of the weapons captured or the rebels who sold or gave the arms to the terror group.
"The main drivers of illicit weapons supplies are not the companies and states that manufacture weapons but the governments and entities that acquire weapons lawfully and subsequently divert them to unauthorized users," the report said.
The secret arms supply is separate from the Pentagon's operation to arm the Syrian Democratic Forces. The report did not find any SDF weapons falling into Islamic State hands.
Damien Spleeters, the lead author of the report, said the Islamic State "has been able to manufacture their own weapons and IED's on an industrial scale thanks to a robust chain of supply" that began in 2014.