A US marine has been killed in al-Anbar province in western Iraq, the military said in a statement, bringing to nine the number of US troops killed on Thursday. "A marine assigned to First Marine Expeditionary Force was killed in action Thursday, 6 January, while conducting security and stability operations in the al-Anbar province," a military statement read on Friday, adding the incident was under investigation. Earlier on Thursday, another marine was killed in al-Anbar and seven US soldiers were killed in a roadside bombing of a Bradley fighting vehicle in Baghdad. The nine soldiers killed made Thursday the deadliest day in 2005 for US forces in Iraq so far. According to the latest Pentagon casualty figures, the deaths raised to 1350 the number of soldiers killed in Iraq since the US-led invasion in March 2003. Of those killed, 1064 soldiers died in combat. **PHOTO CAPTION*** A US marine patrols the restive city of Fallujah, 50 kms west of Baghdad. (AFP)