The latest US claims come days after it emerged that President George W. Bush had approved US action against Iranian agents in Iraq, and against a rising drumbeat of robust US rhetoric on the Islamic Republic.

"We have weapons that we know through serial numbers ... that trace back to Iran," Odierno told the paper, adding that most weapons supplied by Iran ended up with Shiite extremists.

The weapons involved, he said, include RPG-29 rocket propelled grenades that can fire armor piercing rounds, Katyusha rockets and powerful roadside bombs.

"Several Iranians have been detained in raids inside Iraq and some remain in custody. The arrests have provided clues about Iranian operations," Odierno said.

The United States arrested five Iranians at an office in the northern Iraqi city of Arbil on January 11, accusing them of being agents for Tehran, arming militias and inciting anti-US attacks in Iraq.

Rising US accusations on Iran and its nuclear program and the deployment of a second US aircraft carrier battle group to the region have sparked fears in Congress that the Bush administration is contemplating a military strike.

But Bush said in an interview with National Public Radio on Monday that he had no plans to invade Iran but cautioned : "If Iran escalates its military action in Iraq to the detriment of our troops and/or innocent Iraqi people, we will respond firmly."

The president last week authorized US forces to capture or kill Iranian operatives in Iraq, amid charges from Washington that the Islamic republic has been helping insurgents striking at US troops. Tehran denies the charges.

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