Iraq Sunni insurgents turn to armor-piercing bombs

By David Morgan

WASHINGTON (Reuters) - Sunni Arab insurgents in Iraq have developed their own crude versions of the Iran-originated armor-piercing munitions that have been a hallmark of Shi'ite militant roadside attacks on U.S. troops, U.S. defense officials say.

The devices are a form of weaponry known as explosively formed penetrators, or EFPs, which have given Shi'ite militants the firepower to penetrate the heaviest U.S. armor. Iran denies U.S. assertions that it has supplied EFPs to anti-U.S. Shi'ites.

So far, the Sunni versions, first discovered in 2007, have been crude home-made knock-offs of the Iranian-made EFPs, according to U.S. officials.

But officials are concerned that Sunni EFPs could become more deadly if they follow the same path toward sophistication as the most common roadside bombs, known as improvised explosive devices, or IEDs, used throughout Iraq against U.S. forces for much of the war..

"That's a fairly typical trajectory. I would expect (EFPs) to evolve," said Stephen Biddle of the Council on Foreign Relations.

U.S. officials believe the new EFPs are the work of either al Qaeda in Iraq or the Islamic State in Iraq, related networks of Sunni Islamist militants who have recently come under fire from a joint U.S.-Iraqi counterinsurgency operation.

The munitions have shown up in Sunni areas at a time when Islamist groups are particularly vulnerable after being driven from safe havens by U.S. and Iraqi troops aided by U.S.-allied Sunni tribesmen.