'Smoking-gun evidence': Tehran backing terrorists in Iraq

'Smoking-gun evidence': Tehran backing terrorists in Iraq
Coalition forces seize Iranian-made weapons, munitions made in 2006

U.S. officials say they have found smoking-gun evidence of Iranian support for terrorists in Iraq: brand-new weapons fresh from Iranian factories. According to a senior defense official, coalition forces have recently seized Iranian-made weapons and munitions that bear manufacturing dates in 2006.

This suggests, say the sources, that the material is going directly from Iranian factories to Shia militias, rather than taking a roundabout path through the black market. "There is no way this could be done without (Iranian) government approval," says a senior official.

Iranian-made munitions found in Iraq include advanced IEDs designed to pierce armor and anti-tank weapons. U.S. intelligence believes the weapons have been supplied to Iraq's growing Shia militias from Iran's Islamic Revolutionary Guards Corps, which is also believed to be training Iraqi militia fighters in Iran.

Evidence is mounting, too, that the most powerful militia in Iraq, Moktada al-Sadr's Mahdi army, is receiving training support from the Iranian-backed terrorists of Hezbollah.

Two senior U.S. defense officials confirmed to ABC News earlier reports that fighters from the Mahdi army have traveled to Lebanon to receive training from Hezbollah.

While the New York Times reported that as many as 2,000 Iraqi militia fighters had received training in Lebanon, one of the senior officials said he believed the number was "closer to 1,000." Officials say a much smaller number of Hezbollah fighters have also traveled through Syria and into Iraq to provide training.

U.S. intelligence officials believe the number of Al-Sadr's Mahdi army now includes 40,000 fighters, making it an especially formidable force.