(CNN) -- Three people, at least two of them students, were wounded in crossfire as two people shot at each other at a Texas community college Tuesday, a school spokesman said.

One of the shooters was among the wounded and is in custody at the North Harris Campus of Lone Star College, spokesman Jed Young said. The other shooter fled the campus, he said.

A fourth person at the college suffered a heart attack during the shooting, according to a federal law enforcement official who received reports from the scene. Initial reports indicate the shooting occurred at the school's library, the official said.

Maj. Armando Tello of the Harris County Sheriff's Office told reporters that the situation was "ongoing," and that a person of interest had been detained.

"The police believe the danger has been mitigated," Young said. "The school is under control but still being evacuated."

There were more than 10,000 students at the campus at the time of the shooting, Young said.

"Please don't go to campus! If you are on campus. Use caution!" a post on the school's Facebook page said.

Police and emergency responders swarmed an entrance to the campus, aerial video from KPRC showed.

Medical personnel were seen treating at least two people and moving them to ambulances. One person appeared to be handcuffed to a stretcher. Students were jogging away from some buildings, with their hands up in the air, presumably in response to police instruction.

"I heard no less than five shots and I just ran," one student told CNN affiliate KTRK. "My heart was pounding. I was praying I wouldn't hear anymore shots. I was with a bunch of other people running and someone yelled out, 'don't push!' People were crying, I had tears in my eyes."

Another witness told KTRK he saw blood on the ground and someone shot in the leg.

"Beside him, there was one guy in handcuffs," he said.

"I just heard somebody screaming and then after that I heard the shots," another student told KPRC.

The Lone Star College system is the largest institution of higher education in the Houston area, and the fastest-growing community college system in Texas, according to its website.

CNN's Carol Cratty and Devon Sayers contributed to this report.