A suspicious odor prompted the brief evacuation of two University of Minnesota classroom buildings Thursday morning.

A text alert sent to students and others affiliated with the U shortly after 7 a.m. said that the Minneapolis fire personnel and campus police were on the scene of Kolthoff Hall "assessing [a] chemical odor. Stay clear of the area."

The Fire Department said its crews checked on a "possible chemical leak" on the sixth floor. The department said the chemical has yet to be identified.

An additional campus alert said neighboring Smith Hall also was evacuated because the odor "started to drift" into that building, said university spokesman Tim Busse. Kolthoff and Smith are connected by a skyway. They also house science labs and offices.

After emergency personnel "couldn't find anything with their monitors," an all-clear for the two buildings was issued about 8:30 a.m., Busse said.

Busse said the university was notified of the odor shortly after 7 a.m. Classes start at 8 a.m.

Someone in Kolthoff Hall called in the report to authorities and said the suspicious substance was "an eye irritant" to the caller, Busse added.

Kolthoff Hall is located at 225 Pleasant St. SE. and sits just off the Mississippi River, across from the Weisman Art Museum. Smith Hall is just to the north at 207 Pleasant.

Pleasant St. in that area was closed during the brief incident, and buses operated by Metro Transit and the university were rerouted, Busse said.

Anne Millerbernd is a University of Minnesota student on assignment for the Star Tribune.