BAGHDAD, Iraq (CNN) -- A top special operations officer with Lebanon's Hezbollah militia pretended to be deaf and mute when he was captured in Iraq earlier this year, hampering efforts to obtain his identity for weeks, U.S. intelligence officials said.
Brig. Gen. Kevin Bergner announces the capture of Ali Mussa Daqduq at a news conference in Iraq on Monday.
Ali Mussa Daqduq, who U.S. officials say played an integral role in a January attack in Karbala that killed five Americans, allegedly was helping to train Shiite militias fighting U.S.-led coalition forces, the officials said.
Daqduq was arrested in March in the southern city of Basra, and after officials learned Daqduq's identity, the alleged explosives expert began talking, officials said. Watch a report on how Daqduq was captured »
Daqduq was captured in a raid aimed at seizing another Shiite militant leader suspected of involvement in the January 20 Karbala attack, said Brig. Gen. Kevin Bergner.
Intelligence officials said that Daqduq and the Iraqi militia commanders with whom he worked have admitted working with Iran's Quds Force.
The Iranian special operations force "is using Lebanese Hezbollah essentially as a proxy, as a surrogate, in Iraq," Bergner said. He added that the military is learning about the "specific motivations behind those operations."
U.S. commanders have maintained for months that members of the Quds Force, a branch of Iran's Revolutionary Guard, have been training and providing weaponry to Iraqi militants.
Washington repeatedly has accused Tehran of ignoring the flow of weapons and militants across its border with Iraq. U.S. demands that the Islamic republic stop such traffic, coupled with long-standing tensions over Iran's nuclear program, has fueled fears of a wider war in the region.
Iran, which has close ties to the Shiite parties controlling Iraqi Prime Minister Nuri al-Maliki's government, has repeatedly denied the allegations.
U.S. intelligence officials, however, say the Quds Force is trying to model special Shiite groups after Hezbollah, which holds considerable sway in southern Lebanon. The Quds Force has provided weapons and between $750,000 and $3 million to these groups, Bergner said.
"Without this support, these special groups would be hard-pressed to conduct their operations in Iraq," the general said.
The Karbala operation was aimed at taking captives who could be traded for five Iranians held by U.S. troops after a January 10 raid in Irbil in northern Iraq, U.S. and Iraqi militia sources said. But the attack went awry and five Americans were killed, the sources said.
Qais Khazali, a former spokesman for radical cleric Muqtada al-Sadr's Mehdi Army militia, was sought in connection with the attack. When he was arrested in March, he had left the Mehdi Army and was heading one of the special Shiite groups, U.S. intelligence officials said.
In searching for Khazali, troops found Daqduq and computer documents detailing the planning and training for the failed kidnapping, intelligence officials said.
A Hezbollah spokesman in Lebanon said he would not dignify the U.S. allegations with a response.
It's unclear why Hezbollah would send advisers to Iraq, but U.S. intelligence officers say they suspect Hezbollah is indebted to Iran for decades of military and financial support.
Mehdi Army officials deny receiving any military aid, though they say they share some of Hezbollah's ideals.
"I say clearly that we do not accept any logistic, financial or any other kind of support from anyone outside the borders of Iraq," said Rassim al-Marwani, al-Sadr's cultural adviser. E-mail to a friend
CNN's Thomas Evans contributed to this report.