Police surround Concordia University

Montreal police have surrounded several buildings at Concordia University's western campus following reports of an armed gunman Tuesday morning.

A janitor at the university called 911 just before 10 a.m. ET after a man in camouflage and carrying a long black bag was spotted, the reports say.

At least one campus building has been evacuated, and several other buildings are in lockdown.

No gunshots were reported.