Baghdad - Five mortar rounds hit a massive United States military base near Baghdad's airport on Tuesday evening, Iraqi police and American officials said, without any immediate indication of casualties.

"Five mortar rounds were fired from the Jihad district (of southern Baghdad) at the American camp at around 9.30pm," a police official said.

Jihad was once a stronghold of the Mahdi Army, the militia of radical anti-US Shi'a cleric Moqtada al-Sadr.

US spokesperson Major Janet Herrick confirmed the attack.

"Victory Base Complex received indirect fire Tuesday night at approximately 9.30pm," she said.

"Damages are currently being assessed. The incident is currently under investigation." - AFP