A Saturday morning report of a gunman at MIT that prompted a campus-wide lockdown was a hoax, authorities said.

The Cambridge Police Department said it received a report at approximately 7:28 a.m. that a man was inside a building in the Main Group complex on MIT’s campus with a gun. The gunman was reported to have a “long rifle and body armour,” according to an MIT emergency alert message.

CPD officers reached the scene at 7:30 a.m., secured the area, and searched the buildings thoroughly, room-by-room. MIT sent out an emergency message telling students to stay indoors or seek shelter at about 8:45 a.m. But when CPD’s hunt yielded no results, the lockdown was called off at 10:45 a.m.

In a statement released shortly after 12:30 p.m., CPD spokesperson Daniel M. Riviello wrote, “No armed suspects were found in the building or on campus, and police believe that the event, as reported, did not occur.”

The Main Group, which rests at the center of MIT’s campus, comprises a group of facilities under 77 Massachusetts Ave., MIT’s flagship mailing address.

—Staff writer Matthew Q. Clarida can be reached at clarida@college.harvard.edu. Follow him on Twitter at @MattClarida.