An active shooter was being investigated on the Ohio State campus in Columbus, authorities tweeted.

"Buckeye Alert: Active Shooter on campus. Run Hide Fight. Watts Hall. 19th and College" the university's emergency management agency tweeted. Later the agency tweeted a warning to "Continue to shelter in place in north campus area. Follow directions of Police on scene."

A similar message appears atop the school's website: "Buckeye Alert: Continue to shelter in place. Avoid area of College. More information to follow."

The school's website lists Watts Hall as a Materials Science and Engineering building.

"Ohio's thoughts and prayers go out to the Ohio State community," Gov. John Kasich tweeted. "Be safe, listen to first responders."

Tweeted Rep. Tim Ryan, D-Ohio: "Everyone stay safe -- Monitoring this situation closely. Thoughts and prayers with everyone on campus."

Ohio State’s 1,764-acre campus is located about 2.5 miles north of Columbus. The school, founded in 1870, is the third-largest campus in the U.S. with about 45,000 undergraduates and 13,000 post-graduates.

Stay tuned to for updates on this breaking news situation.