Authorities respond to reports of shots fired at the University of Oklahoma's Norman campus on Friday.
CNN  — 

The University of Oklahoma’s campus in the city of Norman is secure and there is no threat to the community, officials said nearly 90 minutes after the school alerted that an active shooter was present on Friday.

Oklahoma State Highway Patrol Trooper Eric Foster confirmed to CNN the campus is safe and that no injuries were reported. University police also issued an “all clear” alert.

“After a thorough search, no threat was found. There is no threat to campus. Alert has been canceled,” the university said on Twitter at 10:53 p.m. CT Friday.

Just before 9:30 p.m. CT, the university tweeted there was an active shooter and urged people to “take immediate action now. Run. Hide. Fight!”

The warning was followed by another tweet indicating campus police were investigating “possible shots fired” on school grounds.

“Avoid South Oval area. Shelter in place,” the university had said.

The shelter-in-place order was lifted after authorities cleared the campus late Friday night.

CNN’s Dave Alsup and Rebekah Riess contributed to this report.