"We have seen ordnance and weapons that come from other places, but we assess that they have come through Iran," US military spokesman Admiral Mark Fox told reporters. "There are missiles that are actually manufactured in China that we assess come through Iran as well."
Fox also alleged Iranian agents continue to smuggle Iranian made armour piercing bombs — explosively-formed penetrators (EFPs) — to Iraqi extremist groups across the country’s long border.
"We do feel that there are networks of EFPs that are coming from Iran," he said, adding the troops had detained two suspects believed to be linked to the Iranian Revolutionary Guards’ covert Qods Force.
"We have detained two suspects near the Iran-Iraq border just this weekend that we suspect to be part of the IRGC-Qods Force network," he said.
The US military has repeatedly accused Iranian linked groups of training Iraqi extremists in the use of EFPs.
Since May 2004, when the EFPs emerged on the Iraqi battlefield, more than 200 US soldiers have been killed by these bombs which fire a fist-sized chunk of molten metal that can cut through even a heavily armoured vehicle.
Tehran denies being behind any weapons smuggling, but Fox insisted that weapons seized by Iraqi and US forces are clearly of Iranian manufacture.
"They are distinctive … in particular mortars, mortar pins, some of the residue that you see from the mortar attacks that are distinctly and uniquely Iranian," he said.
"Also the technologies associated with some of the improvised-explosive devices, some of the triggering mechanisms and also some of the techniques and also the technology associated with manufacture of EFPs are distinctly and uniquely Iranian."