Heightened security will remain in place until next week on the University of Winnipeg's downtown campus after officials found threatening graffiti on a bathroom wall.

A student discovered the threat on the wall of a men's washroom on the first floor of Centennial Hall late Wednesday, university president Lloyd Axworthy said Thursday.

Axworthy would not reveal exactly what the message read, but said it specified an incident that would take place midmorning on Wednesday, Sept. 26, targeting members of the university community.

At one point, Axworthy used the term "personal" to describe the threat, but he later said that it was not aimed at a particular individual.

Winnipeg police Const. Jacqueline Chaput said she'd never seen a threat "of this magnitude" before, adding that an investigation by the force's major crimes unit is underway.

"It might just be a case of graffiti, but it might also be a more serious situation, so the university is treating it seriously," university spokesman Dan Hurley told CBC News Thursday morning.

Classes and university business continued as usual, but some doors to the university were locked Thursday, and police officers were visible on campus.

Students have been asked to carry their student identification with them on campus.

"These days, we can't take anything too lightly of this kind, so the university has taken the extra step to make sure that our campus remains safe and secure as it always has been," Hurley said.

Anyone who knows anything about the warning or sees any suspicious behaviour around the university campus has been asked to call police or university security.