A shooting on a Texas community college campus wounded three people and sent students fleeing for safety as officials placed the campus on lockdown, officials said.
Harris County Sheriff's Maj Armando Tello said authorities had detained a person of interest.
Police also thought there could be a second gunman, according to a law enforcement official in Washington who spoke on condition of anonymity because he was not authorised to discuss the ongoing case.
The shooting comes as the U.S. debates its gun control laws amid a series of mass killings in public venues including schools and movie theatres.
Aerial footage from local television stations showed police cars and ambulances parked on the Lone Star College System campus about 32 kilometres north of downtown 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 hospital following the shooting.
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.
The Lone Star College System has an enrollment of 90,000 students and six college campuses, according to its website.
The latest shooting comes as a 15-year-old boy is still in custody as detectives try to piece together what led to the shooting of five people, including three young children, who were found dead in a New Mexico home.
The teenager was arrested on murder and other charges in connection with the shootings, which happened on Saturday night local time in a rural area south west of central Albuquerque, said Lt Sid Covington, a sheriff's spokesman.
Detectives were working to identify the five victims as well as the teenager's relationship to them.
"Right now we're to the meticulous points of processing the scene and collecting physical evidence, and this is a vast scene with a lot of physical evidence," Lt Covington said.
According to authorities, each victim sustained more than one gunshot wound and several guns were found at the home, one of which was a semi-automatic military-style rifle. Investigators were trying to determine who owned the guns.
Authorities also declined to release details of any conversation that the 15-year-old had with investigators. The teenager was booked on two counts of murder and three counts of child abuse resulting in death.