WASHINGTON - A U.S. air strike killed one of the most senior al Qaeda leaders in Iraq, a Tunisian linked to the kidnapping and killings last summer of American soldiers, a top commander said Friday.

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

Abu Osama al-Tunisi was killed along with two other terrorist suspects in a U.S. F-16 strike that dropped two 225-kilogram laser-guided bombs on a safehouse where they were meeting, said the U.S. Central Command Air Forces.

"Al-Tunisi was one of the most senior leaders ... the emir of foreign terrorists in Iraq and part of the inner leadership circle,'' Anderson told a Pentagon news conference.

Al-Tunisi was a leader in helping bring foreign terrorists into the country, said Anderson, chief of staff to the No. 2 U.S. commander in Iraq, Lt.-Gen. Ray Odierno.

Speaking by videoconference from Baghdad, Anderson said that al-Tunisi operated in Youssifiyah, southwest of Baghdad, and became the overall emir of Youssifiyah in the summer of 2006.

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

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

Specialist David Babineau was killed at a river checkpoint south of Baghdad on June 16, 2006, and Pte. 1st Class Kristian Menchaca and Pte. 1st Class 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 have helped cut in half the 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 that the increase in troops ordered by President George W. Bush in January _ and the increased operations that followed _ have pushed militants into 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 more than 80 per cent of suicide bombings in the country.

Anderson said that he believes al Qaeda leadership is taking stock of its ability to disrupt U.S. and Iraqi government activities in Iraq. He said he thought they would shift their attention back to Afghanistan, where they had safe haven before the U.S. invasion that followed the Sept. 11 attacks.

Asked if he had any evidence they were returning to Afghanistan, Anderson said: "Obviously, they had a base there already and what we would think would be ... they would want to expand that base if they can. The question becomes, how much can they?''

Anderson said he believes al Qaeda is "fractured, ruptured, mitigated'' in Iraq ... and the question becomes, where would they go? What would they do?''

He laid out a series of operations over the last two weeks that led up to the air strike on al-Tunisi in the town of Musayyib south of Baghdad.

He said associates of al-Tunisi's were captured on Sept. 12 and Sept. 14 in Mahmoudiya, where coalition forces targeted the network that helps bring foreign fighters in the southern belts around Baghdad.

More associates were captured over the next few days. On Sept. 25, commanders received information of a meeting between al-Tunisi and other al Qaeda members.

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.