FALLUJAH, Iraq, March 21 (Xinhua) -- U.S. troops were hit in separate roadside bombs and mortar attacks in western Iraq on Tuesday, causing casualties, local residents said.

    "A roadside bomb went off at about 6:45 a.m. (0335 GMT) on the main road of Barwana town near Haditha city, some 250 km northwest of Baghdad," local residents told Xinhua on condition of anonymity.

    The blast occurred as a U.S. military patrol was passing by, destroying a U.S. Humvee and prompting the U.S. troops to cordon off the scene and blocked the main road, they said.

    Another roadside bomb detonated Monday night near a U.S. patrol in the al-Zawiyah village near Haditha city, destroying a U.S. Humvee, they said, adding the U.S. soldiers surrounded the village and searched houses and detaining two suspects.

    It was not clear whether there was any casualties among the U.S. soldiers in the two attacks as the troops sealed off the scenes, witnesses said.

    In separate attack, insurgents lobbed three mortar rounds on a U.S. military base in east of Fallujah, some 50 km west of Baghdad, witnesses told Xinhua.

    "Three mortar rounds rocked the eastern part of Fallujah when they landed the U.S. base outside the city at about 7:00 a.m. (0400 GMT)," they said.

    Ten minutes later, the U.S. troops fired back with artillery shelling at the source of the mortars, they said.

    Iraq's volatile Anbar province, which includes Haditha, Ramadi and Fallujah, has been a hot bed for insurgency since the U.S.-led invasion in March 2003 as insurgents frequently attack U.S. troops and Iraqi governmental forces. Enditem