Three US troops were killed in separate attacks in Baghdad and west of the capital, the military said Sunday. Two Marines assigned to Multi National Force - West were killed Saturday while conducting combat operations in Anbar province, a Sunni insurgent stronghold west of Baghdad, the military said. A roadside bomb killed a Multi-National Division - Baghdad soldier and wounded four others Friday in western Baghdad, the military said separately. A Task Force Lightning soldier also died Sunday in a non-combat related incident, the military said. It provided no more details but said the incident was under investigation.