More than 1.4 million guns were given by the US government to Iraqi and Afghan forces, according to an exhaustive study of the more than $40bn (£36bn) worth of US Department of Defence munitions contracts since 9/11.

The London-based charity Action on Armed Violence (AOAV) spent more than a year analysing the contracts published by the Department of Defence between 11 September 2001 and 10 September 2015, and concluded that at least 1,452,910 firearms had been provided by the US military to their partners in Iraq and Afghanistan, and that the Pentagon has a partial idea of not only the total number, but how and where the weapons are currently being used.

In one example, the group found contracts for weapons with companies, whose clients include Jordan, Kuwait, Saudi Arabia and Iraq, publicly declared as being for ‘Truck Trailer Manufacturing’, but the payments made to the company were listed as being for ‘GUNS, THROUGH 30mm.’

The findings fit with long held anecdotal evidence that US authorities handed firearms to local fighters and militia as part of its ‘war on terror’ with little or no intention of monitoring their use or whereabouts.

The Pentagon has been criticised for not applying to itself the same standards it applies to US troops under its command, who are encouraged to think of their rifle as an extension of their own person, and take meticulous care of ensuring it is never lost or damaged.

A Pentagon spokesperson admitted to the New York Times that there had been “lapses in accountability of some of the weapons transferred.” But he maintained that once a weapon was handed to a foreign fighting force, “It is their responsibility to account for that weapon.”

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It is clear that among the many firearms openly available for purchase on black markets and indeed social media throughout the Middle East were originally provided by U.S. authorities to their associates in Iraq and Afghanistan.

Iain Overton, a former BBC journalist who led the AOAV’s research, said: “Our findings raise concerns about the DoD's transparency and accountability when it comes to issuing contracts.

“It highlights the fact that significant numbers of small arms are sent to foreign governments but are never publicly recorded by the DoD publicly.

“We know by looking at other US government records, that at least 1,452,910 small arms have been sent to Iraq and Afghanistan in the last 14 years.