This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

CHICAGO — One of the nation’s top universities called off classes on the first-day students are due back from the Thanksgiving holiday because of an online threat.

The University of Chicago said all classes and activities are canceled Monday after the FBI passed on an online threat of gun violence on the campus quad at 10 a.m. Monday.

The decision, which the FBI says the university made, could affect more than 30,000 students, faculty and staff who work on the Hyde Park campus south of downtown Chicago.

Students who live on campus are advised to stay indoors. The only facility that remains open is the medical center, which will treat patients but have added security.

The university is ranked No. 4 in the nation by U.S. News and World Report.