Louisiana State University officials aren’t sure when they will lift a campus-wide evacuation order following a bomb threat.

LSU spokesman Herb Vincent says officials hope to reopen the Baton Rouge campus by Monday night, but they aren’t certain if a building-by-building sweep will be complete before Tuesday.

Thousands of students, professors and workers were told to leave the campus Monday morning.

University spokeswoman Kristine Calongne says Chancellor William Jenkins called for the evacuation because of a threat phoned into 911 about 10:32 a.m. The caller didn’t direct the threat to any specific area of the campus.

“Please evacuate as calmly and quickly as possible,” a statement read on the school’s website.

Bomb threats were also made last week at the University of Texas at Austin, North Dakota State University at Fargo, and Hiram College in Ohio.