(Reuters) – A 22-year-old man has been charged in a shooting on a community college campus in Texas that left three people wounded, one critically, authorities said.

Carlton Berry was charged with aggravated assault following the shooting at the Lone Star College near Houston on Tuesday, and was being treated in hospital, said Harris County Sheriff’s office spokesman Alan Bernstein.

The two people involved in the argument were treated in hospital, including a woman with student identification with a medical issue that was not a gunshot wound, authorities said.

A maintenance worker who had been standing nearby was shot in the leg.

No other identifications would be made at this time, Bernstein said

An ambulance dispatcher said his company had transported three people to local hospitals. One of them was in critical condition and the other two were in “urgent” condition, he said.

The shooting at the community college with some 10,000 students was the latest incident at a U.S. school since a gunman massacred 20 children and six adults in Connecticut in December.

The argument began as a verbal exchange and escalated to shooting, authorities said. A handgun was involved but no other information was given about the weapon.

The Lone Star College System is the largest institution of higher education in the Houston area, according to its website. Student enrollment is 90,000 and there are six colleges in the system.

There have been three shootings at schools and colleges in the United States in the past two weeks.

On January 10, a student armed with a shotgun critically wounded a fellow student at a high school in Taft, California, about 30 miles southwest of Bakersfield.

On January 15, a student armed with a pistol opened fire at Stevens Institute of Business & Arts in St. Louis, shooting a school employee and then turning the gun on himself.

Also on January 15, two people were killed and a third wounded when gunfire broke out in the parking lot of a community college in eastern Kentucky. Authorities said that shooting was a result of a domestic conflict.