A Lone Star College spokesperson has confirmed that shots have been fired and evacuations have been ordered on the campus in north Houston.
Emergency responders are focused in the area around the Lone Star campus library. Some students could be seen running from the building.
There is no immediate word on casualties or the shooter.
A student at the college said they heard five shots, and they sounded as if they occurred outside, in an area between the library and the cafeteria.
Other students say they heard gunshots near the cafeteria.
There have been unconfirmed reports of three people injured. Medical crews could be seen tending to at least three victims outside the building.
Their conditions are not known, nor the nature of their injuries. At least one person is being taken by ground ambulance to Ben Taub Hospital.
Some portions of campus are being evacuated, and other students are being instructed to shelter in place, says campus spokesperson Vicki Cassidy.
Aldine ISD has four campuses near Lone Star on lockdown.
Dunn Elementary, Parker Intermediate and Nimitz 9th grade campus and Nimitz HS campus are all being secured; police are monitoring the situation.
The Harris County Sheriff's Office is also on the scene.
Story developing ...
UPDATE: A federal law enforcement official told Fox News that one person is in custody and police are searching the nearby countryside for a second shooter.
Three victims were reportedly transported from the scene to area hospitals; it's unclear if any of them were killed or how severe their injuries are.
Moments after the shooting, students were being led out of the campus with hands on their heads. Police SWAT teams were searching the campus.