BAGHDAD, (AP) – Iran’s elite Quds force helped militants carry out a January attack in Karbala that killed five Americans, a U.S. general said Monday. U.S. military spokesman Brig. Gen. Kevin J. Bergner also accused Tehran of using the Lebanese Shiite militia Hezbollah as a “proxy” to arm Shiite militants in Iraq.

The claims were an escalation in U.S. accusations that Iran is fueling Iraq’s violence, which Tehran has denied, and were the first time the U.S. military has said Hezbollah has a direct role.

A senior Lebanese Hezbollah operative, Ali Mussa Dakdouk, was captured March 20 in southern Iraq, Bergner said. Dakdouk served for 24 years in Hezbollah and was “working in Iraq as a surrogate for the Iranian Quds Force,” Bergner said.

The general also said that Dakdouk was a liaison between the Iranians and a breakaway Shiite group led by Qais al-Kazaali, a former spokesman for cleric Muqtada al-Sadr. Bergner said al-Kazaali’s group carried out the January attack against a provincial government building in Karbala and that the Iranians assisted in preparations. Al-Khazaali and his brother Ali al-Khazaali were captured with Dakdouk.

Dakdouk told U.S. interrogators that the Karbala attackers “could not have conducted this complex operation without the support and direction of the Quds force,” Bergner said.

Documents captured with al-Khazaali showed that the Quds Force had developed detailed information on the U.S. position at the government building, “regarding our soldiers’ activities, shift changes and defenses, and this information was shared with the attackers,” Bergner said.

The Karbala attack was one of the boldest and most sophisticated against U.S. forces in four years of fighting in Iraq, and U.S. officials at the time suggested Iran may have had a role in it.

In the assault, up to a dozen gunmen posed as an American security team, with U.S. military combat fatigues, allowing them to pass checkpoints into the government compound, where they launched the attack. One U.S. soldier was killed in the initial assault, and the militants abducted four others who were later found shot to death.

On Monday, the U.S. military reported the deaths of five U.S. servicemembers killed in fighting a day earlier, including two soldiers killed in attacks in Baghdad and two soldiers and a Marine who died in fighting in western Anbar province. The deaths brought to 3,582 the number of members of the U.S. military who have died since the beginning of the Iraq war in March 2003.

The new accusations against Iran raise tensions between the two countries as Iraq is trying to organize a second round of direct talks between U.S. and Iranian officials in Baghdad. The U.S.-backed, Shiite-led Iraqi government, which has close ties to Iran, is pushing the two to ease their disputes to help reduce Iraq’s turmoil, but a February meeting between the two sides made little headway.

The U.S. military in the past has accused the Quds Force — the external arm of Iran’s elite Revolutionary Guards — of arming and financing Iraqi extremists to carry out attacks on U.S. and Iraqi forces. Tehran has denied the U.S. accusations.

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 they returned to Iraq, they formed units called “special groups” to carry out attacks, bombings and kidnappings.

“Our intelligence reveals that the senior leadership in Iran is aware of this activity,” he said. Asked if Iran’s supreme leader Ayatollah Ali Khamenei could be unaware of the activity, Bergner said, “That would be hard to imagine.”

Hezbollah spokesmen in Lebanon said they were checking into the claims Dakdouk was a member of the group and would not comment. The group has in the past denied any activities in Iraq. In late 2005, British Prime Minister Tony Blair said his government suspected that Iran and Lebanon’s Hezbollah might be supplying technology and explosives to Shiite Muslim militant groups operating in Iraq, but he provided no proof.

Dakdouk was “tasked to organize the special groups in ways that mirrored how Hezbollah was organized in Lebanon,” the general said. Dakdouk was ordered by Hezbollah’s leadership to work with the Quds Force and went to Iran in May 2006 to meet with Quds Force commanders, Bergner said. He then made four trips to Iraq over the next year.

Hezbollah, he said, helps the Iranians as a “proxy … to do things they didn’t want to have to do themselves in terms of interacting with special groups,” Bergner said. He added that Hezbollah did not appear to have an extensive network in Iraq, saying Dakdouk was “being used specifically as a proxy by the Quds Force.

Dakdouk was captured with documents instructing the special groups on techniques, including how to attack a convoy, and a with a personal diary detailing meetings with Iraqi militants. Al-Khazaali also had documents with details on 11 separate attacks on U.S. force, Bergner said.

A total of 18 “higher-level operatives” from the Iranian-backed special groups have been arrested and three others killed since February, Bergner said.