HOUSTON, JAN 23 - One person was in critical condition and two others were taken to hospital with injuries after a shooting broke out between two people on the campus of Lone Star College near Houston on Tuesday, an official with an ambulance dispatch company said.

"We did transport three patients from the scene," said Mark Smith, an official with Harris county Emergency Corps which dispatches ambulances in that area.

"The patients were described as one critical, two as urgent. My understanding is that at least one of the patients had heart issues, not gunshots," he said.

Smith said he had been told that the shooting took place in the school library, which is near the center of the campus.

Sheriff's Office spokesman Armando Tello said, "We do have, we believe, 3 people injured at this time. We also have a person of interest that's being detained." He gave no further details.

A second shooter fled the campus, according to college spokesman Jed Young. Neither police nor Young said whether the second shooter had been apprehended, and it was not clear if the two people involved in the shooting were students.

The shooting took place on the North Harris campus of the community college system. The campus was evacuated and closed for the day, officials said.

The campus is covered with pine trees and local media reported that authorities were searching a wooded area for the second shooter.

Police were stopping traffic at every intersection on the campus. Some vehicles and some pedestrians were allowed to pass but others were turned away.

Four schools in the Aldine district near Lone Star College were locked down, said Leticia Fehling, a spokeswoman for the district. Officials have closed several roads near the college and school buses were not able to enter the area, she said.

Student Amanda Vasquez said she was waiting for an English class to start in a campus building when she heard shots.

"I heard about 6 shots ... Kids started rushing down the hallway. It really happened so fast," she told CNN news.

Vasquez said people in the classroom closed the door, turned off the lights and put a table against the door.

The shooting occurred just over a month after a gunman killed 20 students and six staff at an elementary school in Newtown, Connecticut.

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 college s in the system.

There have been three separate shooting s at schools and college s in the United States in the past two weeks.

On January 10, a student armed with a shotgun opened fire at a California high school, wounding a fellow student. A second student also received minor injures at Taft Union 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 downtown 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.