The United States has put the leader of al Qaida in Iraq on a terrorism blacklist and offered a 10 million US dollar (£6.5 million) reward for information on his whereabouts.
The State Department added Ibrahim Awwad Ibrahim Ali al-Badri, also known as Abu Du'a, to its list of specially designated terrorists.
The move freezes any assets he may have in US jurisdictions and bars Americans from providing him material support.
The State Department did not indicate al-Badri has any holdings in the US. The prohibition against Americans providing him with money or other support is more significant, as is the bounty.
Al-Badri is accused of running al Qaida in Iraq's large-scale operations, including an August 28 attack on a Baghdad mosque that killed a prominent Sunni lawmaker and a major May strike in Hilla that killed two dozen Iraqi police officers and wounded 72 others in retaliation for the killing of Osama bin Laden.
The department said that al Qaida in Iraq, under the direction of al-Badri, had claimed 23 other attacks between March and April.
In August it said the group vowed to carry out 100 attacks throughout Iraq to avenge bin Laden's killing by US special forces.