Houston ? Six people were shot and wounded at a community rally on the Texas Southern University campus Wednesday in what police believe was a gang-related drive-by shooting, a school spokeswoman said.

Witnesses told police that one car drove by an outdoor event on campus, where a popular Houston rapper was promoting voter registration, and opened fire, TSU spokeswoman Eva Pickens said.

Six people were shot, including one male student. They were being treated at hospitals for serious, but nonlife-threatening injuries, Pickens said.

Campus police believe the incident resulted from a rivalry between two gangs, one from Missouri City, a suburb southwest of Houston, and the other from Fresno, a small town outside Missouri City, she said.