US forces in Iraq have killed the alleged mastermind of a guerrilla attack in which five US troops died, military officials have said.
US forces had been hunting al-Dulaimi since the January attack
Azhar al-Dulaimi was killed on Friday during clashes with US troops as they tried to capture him in northern Baghdad, said Maj Gen William Caldwell.
He was believed to be behind a raid in which guerrillas posing as US troops attacked a military base in Karbala.
One US soldier was killed and four others abducted and later gunned down.
US forces had been hunting al-Dulaimi since the sophisticated January attack, in which English-speaking gunmen with American weapons and military uniforms attacked a joint US-Iraqi military headquarters in the Shia city.
"We found him finally Friday morning," Maj Gen Caldwell told CNN.
"We went in on a precision operation to capture him and in the pursuing engagement that occurred, he was killed."
The brazen attack shocked the US military, which was examining how the guerrillas managed to bypass Iraqi security forces to enter the compound.
Meanwhile, thousands of US soldiers are still searching for three colleagues who were abducted south of Baghdad on 12 May.
"We're not going to give up on our soldiers. We have every reason to believe at this point still that they probably are alive," Maj Gen Caldwell said.
Four US soldiers and their Iraqi interpreter were killed in that attack.
The commander of US forces in Iraq, Gen David Petraeus, has said the kidnappers are linked to al-Qaeda.