Four U.S. Marines (search) have been killed in fighting in Iraq's western Anbar (search) province, the military said Wednesday.

Two were killed "as a result of enemy action" on Tuesday while the other two were killed a day earlier, it said in a statement. It provided no other details.

Anbar stretches from the west of Baghdad to the Jordanian and Syrian borders. Its most populous city is Fallujah (search), which Marines have besieged for the past 10 days.