BATON ROUGE, La. (AP) — Louisiana State University officials issued an all-clear Tuesday evening after a report of an armed intruder on campus. LSU spokesman Ernie Ballard said a shelter-in-place order was lifted and the university returned to normal operations after police conducted a room-by-room search of Coates Hall and found no threat. Ballard said LSU officials were aware of a plainclothes police officer who had a visible gun on his belt and was in the building for an event at the time of the report, but they do not know if that's what prompted the report of a gun. The university posted a message on Twitter about 3 p.m. saying an armed intruder had been reported in Coates Hall and police were on the scene. Coates Hall houses academic departments and several student support services, according to the LSU website. The initial tweet advised students and others on the Baton Rouge campus to run, hide or fight. In a later post, university officials said: "The situation is ongoing. No shots have been fired, and there are no injuries. Continue to avoid the area or remain in a safe place." Police had cordoned off an area around the building with tape and several officers were present, but life on the campus appeared to go on without disruption. Students mingled at the student union across the street, and traffic flowed normally. Classes are not in session at the state's flagship university, but many students have been moving back to the school after summer break.