Deadliest Bomb in Iraq Is Made by Iran, U.S. Says

New York Times

WASHINGTON — The most lethal weapon directed against American troops in Iraq is an explosive-packed cylinder that United States intelligence asserts is being supplied by Iran.

The assertion of an Iranian role in supplying the device to Shiite militias reflects broad agreement among American intelligence agencies, although officials acknowledge that the picture is not entirely complete.

In interviews, civilian and military officials from a broad range of government agencies provided specific details to support what until now has been a more generally worded claim, in a new National Intelligence Estimate, that Iran is providing “lethal support” to Shiite militants in Iraq.

The focus of American concern is known as an “explosively formed penetrator,” a particularly deadly type of roadside bomb being used by Shiite groups in attacks on American troops in Iraq. Attacks using the device have doubled in the past year, and have prompted increasing concern among military officers. In the last three months of 2006, attacks using the weapons accounted for a significant portion of Americans killed and wounded in Iraq, though less than a quarter of the total, military officials say.

Because the weapon can be fired from roadsides and is favored by Shiite militias, it has become a serious threat in Baghdad. Only a small fraction of the roadside bombs used in Iraq are explosively formed penetrators. But the device produces more casualties per attack than other types of roadside bombs.

Any assertion of an Iranian contribution to attacks on Americans in Iraq is both politically and diplomatically volatile. The officials said they were willing to discuss the issue to respond to what they described as an increasingly worrisome threat to American forces in Iraq, and were not trying to lay the basis for an American attack on Iran.

The assessment was described in interviews over the past several weeks with American officials, including some whose agencies have previously been skeptical about the significance of Iran’s role in Iraq. Administration officials said they recognized that intelligence failures related to prewar American claims about Iraq’s weapons arsenal could make critics skeptical about the American claims.

The link that American intelligence has drawn to Iran is based on a number of factors, including an analysis of captured devices, examination of debris after attacks, and intelligence on training of Shiite militants in Iran and in Iraq by the Iranian Revolutionary Guard and by Hezbollah militants believed to be working at the behest of Tehran.

The Bush administration is expected to make public this weekend some of what intelligence agencies regard as an increasing body of evidence pointing to an Iranian link, including information gleaned from Iranians and Iraqis captured in recent American raids on an Iranian office in Erbil and another site in Baghdad.

The information includes interrogation reports from the raids indicating that money and weapons components are being brought into Iraq from across the Iranian border in vehicles that travel at night. One of the detainees has identified an Iranian operative as having supplied two of the bombs. The border crossing at Mehran is identified as a major crossing point for the smuggling of money and weapons for Shiite militants, according to the intelligence.

According to American intelligence, Iran has excelled in developing this type of bomb, and has provided similar technology to Hezbollah militants in southern Lebanon. The manufacture of the key metal components required sophisticated machinery, raw material and expertise that American intelligence agencies do not believe can be found in Iraq. In addition, some components of the bombs have been found with Iranian factory markings from 2006.

Defense Secretary Robert M. Gates appeared to allude to this intelligence on Friday when he told reporters in Seville, Spain, that serial numbers and other markings on weapon fragments found in Iraq point to Iran as a source.

Some American intelligence experts believe that Hezbollah has provided some of the logistical support and training to Shiite militias in Iraq, but they assert that such steps would not be taken without Iran’s blessing.

“All source reporting since 2004 indicates that Iran’s Islamic Revolutionary Corps-Quds Force is providing professionally-built EFPs and components to Iraqi Shia militants,” notes a still-classified American intelligence report that was prepared in 2006.

“Based on forensic analysis of materials recovered in Iraq,” the report continues, “Iran is assessed as the producer of these items.”

The United States, using the Swiss Embassy in Tehran as an intermediary, has privately warned the Iranian government to stop providing the military technology to Iraqi militants, a senior administration official said. The British government has issued similar warnings to Iran, according to Western officials. Officials said that the Iranians had not responded.

An American intelligence assessment described to The New York Times said that “as part of its strategy in Iraq, Iran is implementing a deliberate, calibrated policy — approved by Supreme Leader Khamenei and carried out by the Quds Force — to provide explosives support and training to select Iraqi Shia militant groups to conduct attacks against coalition targets.” The reference was to Ayatollah Ali Khamenei, the Iranian leader, and to an elite branch of Iran’s Islamic Revolutionary Guards Command that is assigned the task of carrying out paramilitary operations abroad.

“The likely aim is to make a military presence in Iraq more costly for the U.S.,” the assessment said.

Other officials believe Iran is using the attacks to send a warning to the United States that it can inflict casualties on American troops if the United States takes a more forceful posture toward it.

Iran has publicly denied the allegations that it is providing military support to Shiite militants in Iraq. Javad Zarif, Iran’s ambassador to the United Nations, wrote in an Op-Ed article published on Thursday in The Times that the Bush administration was “trying to make Iran its scapegoat and fabricating evidence of Iranian activities in Iraq.”

The explosively formed penetrator, detonated on the roadside as American vehicles pass by, is capable of blasting a metal projectile through the side of an armored Humvee with devastating consequences.

American military officers say that attacks using the weapon reached a high point in December, when it accounted for a significant portion of Americans killed and wounded in Iraq. For reasons that remain unclear, attacks using the device declined substantially in January, but the weapons remain one of the principal threats to American troops in and around Baghdad, where five additional brigades of American combat troops are to be deployed under the Bush administration’s new plan.

“It is the most effective I.E.D out there,” said Lt. Col. James Danna, who led the Second Battalion, Sixth Infantry Regiment in Baghdad last year, referring to improvised explosive devices, as the roadside bombs are known by the American military. “To me it is a political weapon. There are not a lot of them out there, but every time we crack down on the Shia militias that weapon comes out. They want to keep us on our bases, keep us out of their neighborhoods and prevent us from doing our main mission, which is protecting vulnerable portions of the population.”

Adm. William Fallon, President Bush’s choice to head the Central Command, alluded to the weapon’s ability to punch through the side of armored Humvees in his testimony to Congress last month.

“Equipment that was, we thought, pretty effective in protecting our troops just a matter of months ago is now being challenged by some of the techniques and devices over there,” Admiral Fallon said. “So I’m learning as we go in that this is a fast-moving ballgame.”

Mr. Gates told reporters last week that he had heard there had been cases in which the weapon “can take out an Abrams tank.”

The increasing use of the weapon is the latest twist in a lethal game of measure and countermeasure that has been carried out throughout the nearly four-year-old Iraq war. Using munitions from Iraq’s vast and poorly guarded arsenal, insurgents developed an array of bombs to strike the more heavily armed and technologically superior American military.

In response, the United States military deployed armored Humvees, which in turn spawned the development of even more potent roadside bombs. American officials say that the first suspected use of the penetrator occurred in late 2003 and that attacks have risen steadily since then.

To make the weapon, a metal cylinder is filled with powerful explosives. A metal concave disk manufactured on a special press is fixed to the firing end.

Several of the cylinders are often grouped together in an array. The weapon is generally triggered when American vehicles drive by an infrared sensor, which operates on the same principle as a garage door opener. The sensor is impervious to the electronic jamming the American military uses to try to block other remote-control attacks.

When an American vehicle crosses the beam, the explosives in the cylinders are detonated, hurling their metal lids at targets at a tremendous speed. The metal changes shape in flight, forming into a slug that penetrate many types of armor.

In planning their attacks, Shiite militias have taken advantage of the tactics employed by American forces in Baghdad. To reduce the threat from suicide car bombs and minimize the risk of inadvertently killing Iraqi civilians, American patrols and convoys have been instructed to keep their distance from civilian traffic. But that has made it easier for the Shiite militias to attack American vehicles. When they see American vehicles approaching, they activate the infrared sensors.

According to American intelligence agencies, the Iranians are also believed to have provided Shiite militants with rocket-propelled grenades, shoulder-fired antiaircraft missiles, mortars, 122-millimeter rockets and TNT.

Among the intelligence that the United States is expected to make public this weekend is information indicating that some of these weapons said to have been made in Iran were carried into Iraq in recent years. Examples include a shoulder-fired antiaircraft missile that was fired at a plane flying near the Baghdad airport in 2004 but which failed to launch properly; an Iranian rocket-propelled grenade made in 2006; and an Iranian 81-millimeter mortar made in 2006.

Assessments by American intelligence agencies say there is no indication that there is any kind of black-market trade in the Iranian-linked roadside bombs, and that shipments of the components are being directed to Shiite militants who have close links to Iran. The American military has developed classified techniques to try to counter the sophisticated weapon.

Marine officials say that weapons have not been found in the Sunni-dominated Anbar Province, adding to the view that the device is an Iranian-supplied and Shiite-employed weapon.

To try to cut off the supply, the American military has sought to focus on the cells of Iranian Revolutionary Guard operatives it asserts are in Iraq. American intelligence agencies are concerned that the Iranians may respond by increasing the supply of the weapons.

“We are working day and night to disassemble these networks that do everything from bring the explosives to the point of construction, to how they’re put together, to who delivers them, to the mechanisms that are used to have them go off,” Gen. Peter Pace, the chairman of the Joint Chiefs of Staff, said last week. “It is instructive that at least twice in the last month, that in going after the networks, we have picked up Iranians.”