Officials at the University of Michigan issued a campus-wide emergency alert following an attempted robbery of a cab driver near university-owned buildings east of Ann Arbor.

Spokeswoman Diane Brown says the text message alert went out to students, staff and faculty Thursday morning after officials received reports of shots fired.

The alert was cancelled shortly afterward when two men were arrested.

The Washtenaw County Sheriff's Office said the cab driver picked up a man and a woman at Plymouth and Dixboro, but then got into a disagreement with the man. The man pulled out a gun and fired a shot through the cab's windshield before struggling with the cab driver and taking off. No one was hurt and the couple was arrested a short time later near Gabriel Richard Catholic High School campus.

Investigators said they still have not recovered the gun used in the incident and are asking if anyone finds it to call 911.

A number of colleges and universities are sending out emergency warnings via text messages and emails, primarily in response to recent shooting incidents on and near campuses.