Three people on campus at Lone Star College were injured in what may have been an argument that escalated. Nearby schools went into lockdown as parents waited to pick up their kids. NBC's Janet Shamlian reports.

Three people were wounded Tuesday afternoon when gunfire erupted at a Houston-area community college, law enforcement officials said.

Authorities confirmed at a news conference that two "persons of interest" were involved and wounded in an altercation at the North Harris campus of Lone Star College. A maintenance worker at the college was also shot in the leg during the crossfire, said Maj. Armando Tello, acting sheriff for the Harris County Sheriff's Office. School officials say the worker, in his mid-50s, was in stable condition.

Police later said Carlton Berry, 22, was charged with aggravated assault. He remained in the hospital early Wednesday, Harris County Sheriff's Office Director of Public Affairs Alan Bernstein told NBC News.

Police did not identify the second "person of interest."

Police said a fourth person, a female with a student ID, was transported from the scene to the hospital, for an unspecified "medical condition."

The shooting happened outside in a courtyard between an academic building and a library, Richard Carpenter with the Lone Star College System said. Police were dispatched at 12:51 p.m. CT and were on the scene within two minutes, according to Tello. Police confirmed a handgun was involved, but could not provide more information because the incident remains under investigation.

Several federal officials have said the incident was gang-related, but the exact nature of the relationship remained unclear.

Authorities say the shooting at a Texas community college was the result of an altercation between two people.

The school said on Twitter that the shooting occurred at about 12:31 p.m. Carpenter said the campus will reopen Wednesday.

Live aerial video taken from NBC station KPRC-TV showed emergency crews moving two people on stretchers into ambulances.

Police officers in SWAT gear were shown on the video entering buildings on the campus and bringing out students.

A spokesperson for Ben Taub General Hospital confirmed to NBC News that two patients from the shooting had been treated there. A Houston Northwest Medical Center spokesperson said it had two patients from the Lone Star College incident. Neither hospital would release more information about the patients.

Witness Amanda Vasquez told KPRC she was in English class with about 25 other students when she heard shots fired, she thought in the hallway. She said she got under her desk, while other students ran out of the classroom.

"We closed the door and we put the table against the door," Vasquez said. "And we were hiding and I was just trying to call my mom to let her know I was OK."

Police came in after about 30 minutes and said they could come out, she said.

Jed Young, a spokesman for the college system, told The Associated Press that a "shelter-in-place order" was issued at the college due to reports of a shooter on campus. Students, faculty and staff were advised by the college website to take immediate shelter where they were. The school later said it was on lockdown.

Lone Star College is a community college system based in the Houston region and has six campuses associated with it.

Lone Star's North Harris campus is 20 miles north of Houston in unincorporated Harris County. The campus has roughly 19,000 students.

According to the Lone Star College website, weapons are not allowed on the campus. The school offers firearm safety courses through its Second Amendment Academy.

NBC's Pete Williams, Jonathan Dienst, Vignesh Ramachandran and Matthew DeLuca contributed to this report.