BAGHDAD, April 13 (Xinhuanet) -- A car bomb blew up at a US military convoy in western Baghdad Wednesday, causing some casualties, witnesses said.

    The blast took place at about 9:00 a.m. (0600 GMT) on the main road in Baghdad's western Khadra district, the witnesses said.

    They said the blast smashed the windows of nearby houses and a school close to the explosion scene was also affected, where casualties were possibly caused.

    The wreckage of a destroyed car could be seen which sent black smoke billowing into the sky, the witnesses said.

    It was not clear whether the US troops had any casualties as US Humvees and soldiers sealed off the area and helicopters flew overhead.

    The US military has no immediate information on the incident.    Enditem