The statement from marines based in the town of Falluja said only that the soldier, assigned to the First Marine Expeditionary Force, was killed on Tuesday in al-Anbar province, west of Baghdad.

It gave no other details, in keeping with standard practice.

Al-Anbar province, within which Falluja falls, has witnessed some of the fiercest resistance to US-led forces.

Despite a bloody assault on Falluja late last year, US hopes of crushing the resistance has largely not materialised.