U.S. military officials in Baghdad are accusing the Iranian government of providing sophisticated explosives to Shiite militias in Iran. Iran has denied the charge. But, as VOA correspondent Gary Thomas reports, even if the accusation is true, the arms may not necessarily be destined for attacks on U.S. forces.

The allegation that Iran is providing arms to Iraqi insurgents is not new.

George W. Bush

"Iran is providing material support for attacks on American troops," he said. "We will disrupt the attacks on our forces. We' will interrupt the flow of support from Iran and Syria. And we will seek out and destroy the networks providing advanced weaponry and training to our enemies in Iraq."

But Ken Katzman, a Middle East analyst at the non-partisan Congressional Research Service, believes U.S. troops are not the primary target of the smuggled munitions. He says the Iranians are arming Shiite militias. Yet, he points out, most of the attacks on U.S. forces come from Sunni insurgents.

He said, "Most of the I.E.D.s [improvised explosive devices], most of the roadside bombs, that are having the most effect on American troops are from Sunni insurgents."

"And I have not seen any evidence presented from the military or elsewhere that these Iranian arms are going to Sunni insurgents, which leads me to question what really is the significance," he continued.

Wayne White, former deputy director of Near East affairs for State Department intelligence, disagrees. He notes that some of the arms displayed by officials in Baghdad are armor-piercing rockets - and only the U.S. and Britain have armored vehicles in Iraq.

"Why would anybody be arming anybody there with this kind of munition? Only to get somebody who has got the kind of vehicle that this munition is needed to open up like a can opener. And we are the only ones who have it. This is an anti-American weapon in Iraq," he said.

The U.S. officials contend that the approval to arm the militias comes from what they call the highest levels of the Iranian government, which would mean President Mahmoud Ahmadinejad and Supreme Leader Ali Khamenei.

Ken Katzman says Iran is arming its co-religionist Shiite militias, Katzman believes, in anticipation of an all-out Sunni-Shia civil war.

He said, "My working assumption is that it is broadly approved at the highest levels, which would mean Ahmadinejad, obviously, but also [former president] Rafsanjani and Khamenei, because my analysis is that these weapons are primarily to position Shiite militias for a coming all-out civil war with Sunnis."

"That would be something that all the factions would agree. All the factions in Iranian government want the Shiites to win any possible civil war in Iraq," he added.

The U.S. presentation made to reporters in Iraq marks the first time officials have produced what they say is clear evidence of direct Iranian involvement in the violence in Iraq.

Paul Pillar, a former senior Middle East analyst for the Central Intelligence Agency, says it shows the United States is ratcheting up its anti-Iran rhetoric.

He said, "It is a rhetorical escalation. Clearly there have been other elements and other bits of rhetoric that would support that thesis as well. I think the bigger question then is, escalation for what purpose? Is it just trying to scare the Iranians into, one hopes, making greater concessions on the nuclear issue or something else? Is it more of a reminder to be more careful or constrained on what they do in Iraq? I do not know. It could be elements of those. But some people have speculated it is paving the way for perhaps a more forceful policy against Iran."

Ken Katzman, as well as other analysts, say the Sunni groups get their arms from private sources in the region, as well as from stockpiles from Saddam Hussein's army.