HOUSTON -- An argument at a northern Harris County community college campus escalated to gunfire Tuesday, catching a maintenance man in the crossfire and leaving students and others cowering in classrooms.The gunshots heard shortly after noon sparked fear of another campus massacre just more than a month after 26 people were killed at an elementary school in Newtown, Conn.The shooting occurred between an academic building and the library at the Lone Star College campus.Scores of police cars and emergency vehicles descended on the school in the 2700 block of W.W. Thorne, the Houston Chronicle reported. While paramedics tended to two wounded men, as well as a female student who needed attention for an unspecified medical reason, officers began to scour wooded areas adjacent to the campus looking for the gunman, who had run away.Cars driving along neighboring streets were stopped and inspected, and dog teams went yard to yard searching for the attacker. Meanwhile, four nearby campuses in the Aldine school district were placed on lockdown.A little after 2 p.m., the suspected gunman showed up at Northwest Medical Center, the Chronicle reported. Authorities said he apparently accidentally shot himself in the hip while pulling or replacing his weapon.In a statement, the Harris County Sheriff's Department said one of the men had a student ID and that both remain under armed guard at the hospitals where they are being treated.Student Luis Resendiz, 22, said he was studying on the second floor when shots were heard. An employee called police and then herded the 30 to 40 people in the library into a small room and told them to crouch down, he said.All students eventually were evacuated, running out of buildings as police officers led them to safety.Authorities offered no details about what led to the fight.Mark Zaragosa said he had just come out of an EMT class when he saw two people who were injured and stopped to help them."The two people that I took care of had just minor injuries," he told KHOU-TV. "One gentleman had a gunshot to the knee and the [other] actually had an entry wound to the lower buttocks area."The shooting last month at Sandy Hook Elementary School heightened security concerns at campuses across the country. Resendiz said the Connecticut shooting was the first thing he thought of when he heard gunfire."I didn't think something like this could happen. You don't think about it happening to you," he said.Guns are not allowed on college campuses, but the Texas Legislature this year may debate a bill that would allow them.Richard Carpenter, chancellor of the Lone Star College System, said the campus is a gun-free zone that "has been safe for 40 years.""We think it's still safe," he added. He also described the maintenance man, who was said to be in his 50s and listed in stable condition, as "in good shape."The campus reopened in the late afternoon, with classes expected to resume today.