MINNEAPOLIS (AP) - The University of Minnesota is keeping its main student union closed for the rest of the day but will reopen it Tuesday morning.

Police were called to Coffman Memorial Union on the East Bank campus in Minneapolis late Sunday on a report of a suspicious bag. Authorities decided to keep the building closed until it could be thoroughly searched.

University officials announced Monday afternoon that the union would remain closed for the day but would open at 7 a.m. Tuesday.

University spokesman Tim Busse says officials decided to keep Coffman closed because surveillance video detected someone entering after hours and the bag's contents were a cause of concern. He would not say what was inside.

The FBI and federal Bureau of Alcohol, Tobacco and Firearms are helping in the investigation.