U.S. MAKES CASE THAT IRAN ARMS FLOW INTO IRAQ

BAGHDAD — U.S. defense and intelligence officials sought Sunday to bolster the charge that Iran was providing arms to Shiite Muslim militants in Iraq, displaying munitions and weapons fragments that they said constituted evidence that Tehran was contributing to Iraq's violence.

They also alleged that a group under the command of Iran's supreme leader was behind the smuggling of weapons across the Iran-Iraq border.

The briefing, held under unusually secretive circumstances, featured three U.S. officials, none of whom would be identified, and two tables laden with what they said were uniquely Iranian military hardware and weapons fragments.

The officials said an Iranian weapon known as an Explosively Formed Penetrator had been responsible for the deaths of about 170 of the 3,400 U.S.-led forces killed in Iraq. The armor-piercing devices are used in roadside bomb attacks, which have increased in the last year, the officials said.

The presentation came as tensions continued to mount between Washington and Tehran over Iran's nuclear ambitions and regional aspirations.

With two U.S. warship groups in the Persian Gulf, the allegations raised suspicion that the Bush administration was trying to build a case for war, much as it had used intelligence reports to win support for the U.S.-led invasion of Iraq.

"That's how we got into the mess in Iraq," Sen. Christopher J. Dodd (D-Conn.) said on CBS television. "That's why some of us supported those resolutions, because of doctored information. So I'm very skeptical based on recent past history about this administration."

Some experts wondered whether it was possible to discern the intended uses of such weapons in a situation as complex as Iraq's.

"There is a virtual civil war happening," said Wayne White, a former State Department intelligence analyst who is a scholar at the Middle East Institute, a Washington think tank. "If Iran is passing munitions to Shia militias, it could be more in the context of the ongoing sectarian strife than aimed at the U.S."

The U.S. officials said they wanted to fend off an alarming new type of weapon that was inflicting an increasing number of casualties among American and Iraqi troops. The presentation was a scaled-back version of one postponed two weeks ago amid a dispute within the administration over the strength of the evidence.