This story has been updated.

UPDATE 8:45 p.m. EDT: Police say they are winding up their operation four hours after reports of a gunman on the campus of the University of Toledo in Ohio. The Toledo Blade reported the student union would remain closed, even if police find no sign of a gunman.

UPDATE, 8:04 p.m. EDT: Authorities continue their search for a reported gunman at the University of Toledo in Ohio after an incident in which they say someone may have brandished a weapon inside the student union building. Dozens of police vehicles remain on the scene and a SWAT team entered the student union at about 6:45 p.m., according to the Toledo Blade newspaper.

Students took to social media after a magnitude 4.0 earthquake that shook the region on Saturday and not long after talk turned to the alleged gunman. Some students on campus during the evacuation were seen in the basement of the unversity’s library studying for exams, photos showed.

Original story below.

The University of Toledo student union building in Toledo, Ohio, was evacuated Saturday after reports of a suspicious person holding a gun in the air were reported there. A man has an "assault rifle" inside, one student wrote on Twitter.

Toledo police are on the scene assisting university police, and the school has sent out an alert to students to stay away from the building, as a "dangerous situation" is unfolding there. Students were reportedly "rushed out" of the building. It is unclear whether the purported gunman is a student at the university.

Early in the evening, the Toledo Blade reported that authorities had entered a nearby building and a SWAT team entered the student union at 6:45 p.m.

About 18,000 undergraduates and 5,000 postgraduates study at the university. This time of year is typically when American colleges hold their final examinations before summer break. This story will be updated as information rolls in.