A senior leader of al-Qaeda in Iraq was killed in a US air strike near Baghdad on Tuesday, the US military reports.
The US military said Abu Osama al-Tunisi was a "key loss" to al-Qaeda
Gen Joseph Anderson said the death of Abu Osama al-Tunisi, who had led a group of foreign militants in Iraq, was a major blow to the organisation.
The US general accused him of leading a cell responsible for kidnapping and killing three US soldiers in June 2006.
The group is linked to some of the bloodiest insurgent attacks in Iraq since the 2003 US-led invasion.
It was led by the Jordanian militant, Abu Musab al-Zarqawi, until he was killed by a US air strike in June 2006.
Speaking to US reporters via videolink from Iraq, Gen Anderson said US aircraft had attacked a target near the town of Musayyib, south of Baghdad, after learning Tunisi was meeting with other al-Qaeda members.
"His presence was confirmed by one of the two detainees from the operation, one who left the target area just prior to the air strike, who we eventually captured minutes later," the chief of staff of Multi-National Corps Iraq said.
US ground forces later recovered a handwritten note believed to have been written by Tunisi at the site, Gen Anderson added.
"The key points in this hand-written note include, he's surrounded, communications have been cut and he's desperate for help," he said.
"What I make of that is that we're having great success in isolating these pockets. They are very broken up, very unable to mass, and conducting very isolated operations."
The general said that Tunisi had been in line to succeed al-Qaeda in Iraq's current leader, believed to be Egyptian militant Abu Ayyub al-Masri.
Tunisi had also, he added, been in overall charge of a cell in the town of Yusufiya, an insurgent stronghold, and had been "responsible for kidnapping American soldiers in June 2006".
One US soldier was killed and two others abducted while guarding a bridge south of the capital on 16 June 2006.
The mutilated bodies of the kidnapped soldiers were found three days later.