The gunfire took place over gang-related violence after a passing vehicle opened fire around the campus of the Texas Southern University in Houston, local police said.
The victims have been rushed to local hospitals where some of them are being treated for serious injurious. One male student was among the six people who were shot and treated for serious, but non-life-threatening injuries, TSU spokeswoman Eva Pickens said.
Witnesses told police that one car drove by and opened fire on the parking lot where a popular Houston rapper was promoting community service and voter registration, The New York Times quoted Pickens, as saying.
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.
Among the rally participants was Houston City Councilman Peter Brown, who is running for mayor in November"s election. Texas Southern is a historically Black university in Houston with an enrollment approaching 10,000 students.