Three US Marines were killed by a roadside bomb in western Iraq, the military said Friday. During subsequent fighting, the surviving Marines in the convoy killed two insurgents and detained four suspected of involvement in the attack near the village of Nasser Wa Salaam, 40 kilometers (25 miles) west of Baghdad, the military said. Thursday's fighting involved Marines of the Regimental Combat Team 8, 2nd Marine Division, II Marine Expeditionary Force (Forward). The names of the deceased are being withheld pending notification of their relatives. The deaths raised to at least 1,991 the number of members of the US military who have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.