A spokesman for US Central Command said initially that the Trijicon sights did not violate the ban and compared the references on the sights to the “In God We Trust” inscription printed on US currency.

On Thursday, however, General David Petraeus, Central Command’s chief officer, called the references “disturbing”.

“This is a serious concern to me and the other commanders in Iraq and Afghanistan,” he told an audience at the Centre for Strategic and International Studies in Washington.