Washington ? U.S. forces in Iraq captured a leader of the insurgency who is believed to be a close associate of Abu Musab Zarqawi, described by some as a key link between the al-Qaida terrorist network and toppled Iraqi leader Saddam Hussein, a senior American official said Friday.

U.S. troops captured Husam al-Yemeni last Thursday, the official said, speaking on condition of anonymity. He is described by U.S. officials as the leader of an insurgency cell in Fallujah, west of Baghdad.

The official said al-Yemeni is the highest-level member of Ansar al-Islam captured so far. That is a group comprising mainly ethnic Kurds from northern Iraq with alleged al-Qaida ties.

Zarqawi is a high-priority target for U.S. forces in Iraq. He is a Jordanian operative the CIA describes as a close associate of al-Qaida leader Osama bin Laden. Zarqawi is suspected of coordinating anti-U.S. operations in Iraq. He may be inside that country, although his whereabouts are unknown.

The official who disclosed al-Yemeni’s capture on Friday said he could provide no more details, including the location where the prisoner was grabbed inside Iraq.

Ansar al-Islam operated in a region of northern Iraq that was outside of Saddam’s control before the war. It was bombed by U.S. warplanes during the fighting.

Now, surviving Ansar members serve as guides and fixers for foreigners entering Iraq, officials say.

In recent months, U.S. forces in central Iraq have detained a handful of people suspected of having ties to al-Qaida, but American intelligence officials described them as mostly low-level operatives with unclear purposes in the country.