Three people have been injured in a shooting at a community college in Texas, authorities said.
Harris County Sheriff’s spokesman Armando Tello also said one person of interest had been detained.
The shooting took place at the Lone Star College System campus, about 20 miles north of central Houston.
A college official said the campus had been placed in lockdown.
Authorities also thought there could be a second shooter, according to a law enforcement official in Washington.
The shooting comes as the US debates its gun control laws amid a series of mass killings in public venues including schools and cinemas.
Aerial footage from local television stations showed police cars and ambulances parked on the Lone Star College System campus about 20 miles (32 kms) north of central Houston. Emergency personnel could be seen tending to people on stretchers, while others ran from a building led by officers.
The Harris County Sheriff’s Office had no immediate details, but college spokesman Jed Young confirmed the campus was put on lockdown following reports of a shooter. The college issued an alert on its website telling students and faculty to take immediate shelter or avoid the campus.
Melinda Muse, spokeswoman for the Harris County Health System, said two people were taken to Harris Health Ben Taub Hospital Emergency Centre following the shooting.
Ms Tello said three people had been injured.
Cody Harris, 20, he said he was in a classroom with about six or seven other students waiting for a psychology class to start when he heard eight shots. He and other students looked at each other, said “I guess we should get out of here,” and fled.
“I was just worried about getting out,” Harris said. “I called my grandmother and asked her to pick me up.”
The Lone Star College System has an enrolment of 90,000 students and six college campuses, according to its website.
Along with the college, four nearby schools in the Aldine Independent School District went into lockdown, a district spokesman said.
Lone Star student Daniel Flores, 19, said he was in a tutoring lab on the second floor doing homework when he heard what he heard six to seven shots.
“I didn’t think they were shots,” he said. “It sounded like someone was kicking a door.”
About 60 people were in the lab, and they began running out of the room once they realised the sound was gunfire, he said. They fled to a nearby student services centre, where authorities kept them there for about 30 minutes before letting them go.
"Lone Star College in Houston on lockdown after reports of gunman on campus. Local TV shows people on stretchers." -- CNN
— Drew Kyndall Ross (@DrewKyndall) January 22, 2013
Breaking: Lone Star Community College in Houston is on lockdown due to a school shooting. Police are still looking for the second shooter.
— Krystal Franklin (@krysfranklintv) January 22, 2013