US forces have carried out a series of air strikes on suspected militant targets on Iraq's border with Syria.
The US military said it believed an al-Qaeda operative known as Abu Islam - an alias used by several militants - was killed in the raids.
Reports say at least 47 people died in the strikes, near the western city of Qaim, in which three houses were hit.
The area around Qaim is believed by US forces to be a route for foreign fighters entering Iraq from Syria.
The Euphrates Valley region has seen regular clashes between the US military and insurgents since the 2003 invasion.
Precision-guided bombs
A US military spokeswoman said the first strike had seen four bombs dropped on one building in the town of Husaybah, near the city of Qaim.
Two more bombs were used in a second strike in the same town on a house "occupied by Abu Islam, a known terrorist", she said.
"Islam and several other terrorists were killed in that attack," she stated.
The third strike, using precision-guided bombs, was on a house in nearby Karabila, to which suspected associates of Abu Islam had fled.
The BBC's Jon Brain in Baghdad says the name Abu Islam is an alias used by several known Islamist militants.
It is not yet clear whether any civilians are among those killed in the air strikes, he says.
Officials said violent clashes had occurred in the area between two rival Sunni Arab tribes, one pro-insurgent and the other loyal to the Iraqi government, over the weekend.
They followed a decision by Sunni leaders to reject the Shia- and Kurd-backed Iraqi draft constitution, approved by parliament on Sunday.