The University of South Carolina has lifted an alert initially triggered by a potential active shooter threat near a library on its main Columbia campus. This alert came shortly after similar false active shooter warnings at Villanova University and the University of Tennessee at Chattanooga, which had also caused chaos and temporary lockdowns as the institutions commenced their fall semesters.

USC students were told to shelter in place Sunday while police investigated an unconfirmed report of an active shooter near the library. Officials later said there was no evidence of a shooter, and there were no reports of any shots being fired.

University spokesman Jeff Stensland said in a statement that the original alert “was sent out of an abundance of caution” and that law enforcement was clearing the library building, going floor by floor — “again out of an abundance of caution, we’re going through the library to make sure.”

Stensland said there were two minor injuries related to the evacuation of the library building.

The school sent an alert of a possible shooter shortly after 6:45 p.m. ordering students to evacuate the area near the Thomas Cooper Library, seek shelter and barricade themselves if necessary. It was followed by another alert saying there was no evidence of an active shooter “at this time. Police are searching affected buildings. Please continue to shelter in place until there is an all clear.”

Approximately 38,000 students attend the school in the heart of the city that’s home to nearly 145,000 people.

The alerts and uncertainty about a shooter search came after the false reports of active shooters at Villanova University and the University of Tennessee at Chattanooga.

In Pennsylvania, someone called 911 reporting a shooter in a Villanova law school building with at least one wounded victim. Students received texts from the school’s alert system, but the school’s president later said it was a hoax.

In Tennessee, the university locked down its campus, telling students: “Possible active shooter in the University Center or Library. Run. Hide. Fight. More info forthcoming.” The lockdown was lifted after multiple law enforcement agencies responded. School officials said there was no evidence of any threat.