Insurgents in the western Iraqi province of Anbar have killed four US soldiers, the US military said Friday.
The marines were killed in fighting on May 2, the military said.
Two army contract workers were killed Thursday in a rocket attack on a coalition base in the southern city of Basra, dpa reported.
Four civilians and four soldiers were injured in the attack.
"This was the first attack of this kind in Basra since March 27," a military spokesman said.
Suspected al-Qaeda terrorists attacked a patrol Thursday evening near the city of Ramadi in the west of the country, Aswat al-Iraq news agency reported.
They killed four Iraqi soldiers and injured nine, the report said.
The US Army got involved in the fighting and killed six of the attackers, the report said.
An al-Qaeda commander by the name of Abu Qatada, believed to be from Saudi Arabia, was killed by US troops Thursday evening near the northern city of Samarra, security sources said.
There was no evidence Friday to back up a claim made by the Iraqi Interior Ministry on Thursday that it had located Abu Hamza al- Mujahir, believed to be the leader of the al-Qaeda terrorist network in Iraq, near the city of Mosul.
The ministry claimed police had arrested al-Mujahir overnight.
There have been contradictory reports about the al-Qaeda leader's identity for years.
US Army officials had speculated that al-Muhajir was an Egyptian, who also goes by the name of Abu Ayyub al-Masri.
Abu Omar al-Baghdadi, who is also sometimes named as the al-Qaeda leader in Iraq, is considered a frontman or an invention of the terrorists who want to give al-Qaeda an "Iraqi face."
An Iraqi police official said on Wednesday that al-Baghdadi was the leader of the so-called Islamic States in Iraq.
The official said that al-Baghdadi was a former officer in the Iraqi Army from the city of Haditha, called Hamid Daud Assawi.