United States officials say Iraqi forces have killed a senior aide to the militant leader, Abu Musab al-Zarqawi.
Zarqawi and his group are believed to behind a string of attacks in Iraq
Officials said Abu Zubair was shot dead in the northern city of Mosul, in an ambush set by Iraqi forces.
He had been wanted for his alleged role in several attacks, including a attack on a police station in Mosul last month, which killed five policemen.
No other details of the operation were provided, and there is no independent confirmation of the US statement.
Abu Musab al-Zarqawi and his group are believed to be behind the kidnapping and beheading of several foreigners in Iraq.
His group - originally known as Tawhid and Jihad, but now known as al-Qaeda in Iraq - is also believed to be behind a long list of suicide bombings and attacks on Iraqi and US forces.