The University of Oklahoma has found "no evidence" that a shooting took place on campus right after ordering a campus-wide lockdown, according to Reuters.

The incident occurred at around 11:20 a.m. local time (12:20 p.m. ET) while classes were being held.

The school confirmed on its Twitter account that police are still searching near Gould Hall where reports were received of a possible shooting.

Approximately 30,000 students attend the university, according to Reuters. Students and faculty members were informed about the incident via text message.

Students were initially told to take shelter for about 30 minutes, according to CNN.

Besides Gould Hall, normal operations have since resumed on campus, according to the University.

University President David Boren said that the incident was likely a "false alarm" caused by a machinery backfire, according to The Oklahoma Daily newspaper's Twitter account.

Dozens of emergency vehicles were on campus to assist with the incident, according to CNN.

The incident took place just a day after a man was shot and killed at Purdue University in Indiana. One suspect was taken into police custody shortly after the shooting.

Gun laws in the U.S. have been a controversial topic since December 2012, when 20 children and six faculty members were killed by a shooter at Sandy Hook elementary in Connecticut. 

Last week two students were shot in a high school in Philadelphia, and another was shot at a high school in Georgia.

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