U.S.-led forces have killed one of the most important leaders of Al Qaeda in Iraq, a Tunisian believed connected to the kidnapping and killings last summer of American soldiers, a top commander said Friday.

Brig. Gen. Joseph Anderson said the death of the terrorist in a U.S. airstrike Tuesday south of Baghdad, and recent similar operations against Al Qaeda, have left the organization in Iraq fractured.

"Abu Usama al-Tunisi was one of the most senior leaders ... the emir of foreign terrorists in Iraq and part of the inner leadership circle," Anderson said.

Al-Tunisi was a leader in helping bring foreign terrorists into the country and his death "is a key loss" to Al Qaeda leadership there, Anderson told a Pentagon news conference.

"He operated in Yusufiyah, southwest of Baghdad, since the second battle of Fallujah in November '04 and became the overall emir of Yusufiyah in the summer of '06," Anderson said in a videoconference from Baghdad.

"His group was responsible for kidnapping our American soldiers in June 2006," Anderson said.

He did not name the soldiers and Pentagon officials said they did not immediately know whom he was referring to. But three U.S. soldiers were killed that month in an ambush-kidnapping that happened while they were guarding a bridge.

Spc. David J. Babineau was killed at a river checkpoint south of Baghdad on June 16, 2006, and Pfc. Kristian Menchaca and Pfc. Thomas Tucker were abducted. The mutilated bodies of the kidnapped soldiers were found three days later, tied together and booby-trapped with bombs.

Anderson said recent coalition operations also have helped cut in half the previous flow of foreign fighters into Iraq, which had been at about 60 to 80 a month.

He credited the work of the Iraqi Department of Border Enforcement and U.S. teams.

Commanders have said previously that the increase in troops ordered by President Bush in January — and the increased operations that followed — have pushed militants into the remote parts of the north and south of the country. Additional operations have been going after those pockets of fighters.

"We're having great success in isolating these pockets," Anderson said.

"They are very broken up, very unable to mass, and conducting very isolated operations," he said. He could not estimate the number of foreign fighters in Iraq but said they commit over 80 percent of suicide bombings in the country.

Anderson laid out a series of operations over the last two weeks that led up to the air strike that killed al-Tunisi in the town of Musayib.

He said an associate of al-Tunisi's was captured in one mission on Sept. 12 in Baghdad and another with links to him was captured Sept. 14 in Mahmudiyah when coalition forces targeted the network that facilitates the flow of foreign fighters in the southern belts around Baghdad.

More associates were captured over the next few days. On Sept. 25, commanders received information that a meeting was taking place near Musayib with al-Tunisi and other Al Qaeda in Iraq members. A U.S. Air Force F-16 aircraft attacked the target.

Al-Tunisi's presence was confirmed by a detainee who had just fled the area before the attack and was captured minutes later, Anderson said.