Baghdad - In some of its most direct accusations against Iran yet, the US military said on Monday senior leaders in Tehran know about operations in which Iran's Qods Force foments violence in Iraq.

A US military explosives expert displays explosives used by Iraqi militants, including the 'EFP' armour-penetrating roadside bomb, in the Green Zone in Baghdad, July 2, 2007. [Reuters]

Military spokesman Brigadier-General Kevin Bergner said the Qods Force was also using the Iranian-backed Lebanese Shi'ite militia group Hezbollah to sponsor militant activity in Iraq.

Iran does not officially acknowledge the Qods Force. Military experts and some exiled Iranians say it is a wing of Iran's Revolutionary Guards that operates abroad and reports directly to Iran's Supreme Leader Ayatollah Ali Khamenei.

Bergner said the Qods Force was involved in a brazen attack in the city of Kerbala in January when gunmen disguised as Americans made their way into a government compound and killed one US soldier and seized four others whom they later killed.

Washington has long accused the Qods Force of arming and training Shi'ite militants who attack US and Iraqi soldiers but previously it said it was not clear whether these actions were carried out with the full knowledge of Iran's leadership.

Shi'ite Iran denies involvement in violence in Iraq and blames the US-led invasion in 2003 for the bloodshed.

"Our intelligence reveals that senior leadership in Iran is aware of this activity," Bergner told a news conference. "We also understand that senior Iraqi leaders have expressed their concerns to the Iranian government about the activities."

Three Camps

Bergner said the United States had discovered the existence of three small camps near Tehran where Iraqi Shi'ite militants were trained by Qods Force and Hezbollah operatives. Between 20-60 militants were trained at any given time, he said.

The Kerbala attack was one of the boldest against US troops. The attackers spoke English, wore American-looking uniforms and carried US-type weapons, which got them through Iraqi checkpoints to reach the compound.

"The Qods Force had developed detailed information regarding our soldiers' activities, shift changes and defenses, and this information was shared with the attackers," Bergner said.

He also said a Hezbollah veteran, Ali Mussa Daqduq, was detained in southern Iraq in March. Daqduq was there to organize secret cells to mirror Hezbollah's structure in Lebanon, he said.

A Hezbollah spokesman in Beirut said he was aware of Bergner's accusations, but had no immediate comment.

Iran's Defense Minister Mostafa Mohammad Najjar dismissed on Sunday as a "sheer lie" US accusations that Iran was militarily intervening in Iraq and supported Iraqi militants, the official IRNA news agency reported.

The fresh charges against Iran come at a sensitive time.

On Sunday, Iraqi Foreign Minister Hoshiyar Zebari told Reuters he was pressing the United States and Iran to hold a second round of talks in Baghdad to follow up a landmark meeting on May 28, but that no date had been set.

The May meeting between US Ambassador to Iraq Ryan Crocker and his Iranian counterpart Hassan Kazemi-Qomi was the most high-profile meeting of the two foes in almost three decades.

Both envoys described the talks as positive.

In fresh violence, the US military said four US soldiers and one Marine were killed in various attacks in Iraq on Sunday, marking a bloody start to the month for American forces.

In Baghdad, where US forces are pushing an aggressive security clampdown to stem sectarian violence, police said a car bomb parked beside a market killed nine people and wounded 33 on Monday.