Traffic stands still near LSU's campus Sept. 17, 2012.

Students, professors and staff at Louisiana State University were allowed to return to the school’s main campus in Baton Rouge Monday night, hours after a bomb threat forced a full-scale evacuation, school officials said.

“All classes and events scheduled for Tuesday, Sept. 18 will be held as planned, and university employees and students should plan to return to their normal schedules on Tuesday,” LSU’s website said Monday night.

LSU Police and other law enforcement agencies are still investigating the origin of the threatening call.

Law enforcement officials had been on high alert since a call came in at 11:32 ET saying there was a bomb on the university’s grounds, university spokeswoman Christine Calongne said.

View the latest developments on breakingnews.com

Students and staff were sent text messages and an alert was posted on the campus website warning, "A bomb threat has been reported on the LSU campus. Please evacuate as calmly and quickly as possible."

Classes and a news conference with LSU football coach Les Miles were canceled Monday due to the threat, officials said. Students and staff were asked to stay off campus as the university investigated the bomb threat.

"It is important for all members of the LSU community -- faculty, staff and students -- to remain off campus unless specifically instructed to return," the university said on its website.

Capt. Doug Cain of the Louisiana State Police told The Associated Press that state police bomb technicians were on the scene. Cain said police were talking to their counterparts in both Texas and North Dakota where university bomb threats were reported last week.

Traffic was at a standstill as the main campus’s 30,000 students, professors and staff evacuated school grounds. Buses loaded with students barely moved from the central part of LSU’s campus, according to The Advocate in Baton Rouge.

Andrew Arceneaux, an LSU student studying business administration, joined other students and waited for buses to arrive so they could leave campus.

“I was in the middle of taking a test and they walked in and told us we had to leave campus,” Arceneaux told the Advocate.

Both the University of Texas in Austin and North Dakota State in Fargo received threats on Friday. The threats prompted the evacuation of both campuses. No explosives were found at either university.

More content from NBCNews.com:

Follow US News from NBCNews.com on Twitter and Facebook