The city in the southern state of Louisiana was plunged into a panic early on New Year's Day when a US army veteran, who the FBI said had pledged loyalty to IS, ploughed a pickup truck into revellers in the crowded French Quarter, famed for its nightlife.

Police killed the suspect in an exchange of fire.

Iraq's Supreme Judicial Council said that an IS member "was arrested for inciting the January 2025 truck attack in the United States" after Iraq received a request from Washington to assist in the investigation.

It added that the suspect is "a member of the external operations office of the Daesh terrorist organisation", using the Arabic acronym for IS.

The suspect will be tried in Iraq under the anti-terrorism law, it said.

Although the country proclaimed the defeat of the jihadist group on its territory in 2017, IS cells have remained active and carry out sporadic attacks against the army and police.

A recent UN report said government-led counter-terrorism operations have resulted in the deaths of nearly half of IS's senior leaders in Iraq.

IS declared a "caliphate" in 2014 after capturing large parts of Iraq and Syria, beginning a rule marked by atrocities.