US forces for the first time accused Hezbollah of playing a direct role in the violence plaguing Iraq, as America hardened its rhetoric against the group’s backers in Iran.

Brigadier General Kevin Bergner, a US military spokesman in Baghdad, accused Hezbollah, a Lebanese Shia group which is funded and trained by Iran, of fomenting violence in Iraq along with an overseas wing of Iran’s Revolutionary Guards.

Brig Gen said it “would be hard to imagine” that Tehran’s elite Quds force would be operating inside Iraq without the knowledge of Iran’s supreme leader Ayatollah Ali Khamanei.

His comments followed the capture and questioning of a senior member of the Lebanese Shia militia inside Iraq.

He accused the Quds force of helping a group of militants carry out an attack in Karbala, south of Baghdad, in January in which five American soldiers were killed.

The latest allegations will ratchet up tensions between the United States and Iran.

The Islamic republic denies involvement in Iraq’s insurgency and blames the US-led invasion in March 2003 for the ongoing bloodshed.

Brig Gen Bergner said that US-led forces in March captured a top Hezbollah militant, Ali Musa Daqduq. He finally confessed to training Iraqi extremists in Iran to carry out attacks in Iraq after initially pretending to be deaf and mute.

“In 2005, he (Daqduq) was directed by senior Lebanese Hezbollah leadership to go to Iran and work with the Quds force to train Iraqi extremists,” Brig Gen Bergner said.

Daqduq also acted as a liaison between the Iranians and a breakaway Shia militant cell led by Qais al-Kazaali, a former spokesman for the radical Shia cleric Muqtada al-Sadr.

This rogue cell carried out the January attack against a provincial government building in Karbala and the Iranians assisted in preparations, according to the military spokesman.

The group behind the Karbala assault has also been linked by General David Petraeus, commander of US-led forces in Iraq, with the kidnapping of five Britons from a Finance Ministry building in Baghdad at the end of May.

Gen Petraeus told The Times that the kidnappers “are trained in Iran, equipped with Iranian (weapons), and advised by Iran”.

According to Brig Gen Bergner, Daqduq told US interrogators that the Karbala attackers “could not have conducted this complex operation without the support and direction of the Quds force”.

The Karbala attack was one of the boldest against US forces in four years of fighting in Iraq.

In the assault, up to a dozen gunmen posed as an American security team to pass checkpoints into the government compound, where they launched the attack. One US soldier was killed in the initial assault. Four others were abducted and later found shot dead.

The kidnapping of the four British security guards and one computer expert was similarly audacious. Scores of vehicles packed with gunmen in commando gear drove up to the Finance Ministry building in broad daylight and snatched the victims. There has so far been no word on their fate, with British and Iraqi authorities still trying to locate the men.

The new, US accusations against Iran raise tensions between the two countries as Iraq is trying to organise a second round of direct talks between American and Iranian officials in Baghdad.

The US-backed, Shia-led Iraqi Government wants the two sides to resolve their differences to help restore peace in Iraq, but a meeting in May produced slim results.

Brig Gen Bergner said Iraqi extremists were taken to Iran in groups of 20 to 60 for training in three camps “not too far from Tehran.” When the militants returned to Iraq, they formed units called “special groups” to carry out attacks, bombings and kidnappings. The Quds force and Hezbollah were jointly operating camps near Tehran in which they trained Iraqi fighters before sending them back to Iraq to wage attacks, the US military spokesman said.

When contacted in Beirut, a Hezbollah official expressed ignorance over the accusations.

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