Authorities briefly locked down the University of Oklahoma after reports of gunfire in a campus building.
President David Boren says a faculty member called police to report hearing three shots being fired in Gould Hall around 11:15 a.m.
The university was placed on lockdown and Gould Hall was evacuated.
The lockdown was lifted 45 minutes later after police were able to search the building and found no evidence.
"It appears to be a false alarm," Boren said.
President Boren commended students and faculty for responding quickly to the lockdown and the faculty member who reported hearing the noises.
"The faculty member did exactly the right thing," Boren said. "That's exactly what should be done."
Boren speculated the noise could have been from a campus construction project.
All campus activities have resumed. Gould Hall will reopen this afternoon after police do a second sweep of the building.