PITTSBURGH — Carnegie Mellon University in Pittsburgh today evacuated three buildings on campus because of an unspecified and so far unconfirmed security threat.

The school alerted students to leave the buildings using a text messaging system that sends warnings to cell phones.

Pittsburgh and campus police were on the scene early this afternoon.

Police have not said what prompted the evacuations, and campus spokesman Ken Walters said only an "unconfirmed security threat" was received late this morning.

The school has evacuated three classroom building, Wean, Doherty and Hamerschlag halls, so police dogs and officers can search them.

Walters said the evacuations began about noon.

By The Associated Press