A student serving at the Reserve Officers' Training Corps (ROTC) caused the lockdown of the California State University at Dominguez Hills near Los Angeles on Thursday, authorities said.
University officials lockdowned the university earlier in the day after someone reported seeing a man carrying a gun on the campus.
According to university officials, campus police and Los Angeles County sheriff's deputies began a search of the campus and put up an "emergency notice" on the university Web site which read:
"The campus is closed and classes are canceled until further notice due to an emergency situation on campus. Students, faculty and staff are asked to stay at home."
The ROTC student went to the campus police station and was interviewed, and it was determined that the rifle was the type used in drills, said Sgt. Craig Calzada of the sheriff's Carson Station.
Later, another notice was posted on the university's Web site noting that "it has been determined that there is no longer a threat on campus."
University spokeswoman Amy Bentley-Smith said the campus was re-opened and classes had resumed.