About 100 university students in Halifax marched in protest against a philosophy professor who posted caricatures of the Muslim Prophet Muhammad on his office door.

The protesters chanted "Peter March is a fool, we don't want you in our school."

Tensions rose briefly when students discovered March, the St. Mary's University professor whose actions sparked the protest joining in at back of the crowd. The students were from Dalhousie and Saint Mary's Universities.

There was a short period of yelling and pushing as March was surrounded by a group of men who shouted that it was wrong for him to show up.

Other students quickly intervened, saying the professor is hungry for media attention and should be ignored.

March said he attended the protest to provoke a discussion of freedom of expression.

March posted the cartoons, which were first published in a Danish newspaper, on his office door on Tuesday. He removed them the same day when asked to do so by the university administration.

The caricatures are considered to be a severe insult to Islam and have sparked riots around the world.

The president of the Saint Mary's University faculty union said the administration did not violate March's academic freedom when it ordered him to remove the cartoons.

March defended his action in the name of academic freedom and freedom of speech but Steven Smith said posting the cartoons did not invite discussion and was not an honest search for knowledge.

"You have a duty that you must deal with research and investigation," Smith said. "You have to have an honest search for knowledge, which is where the classroom and peer review research is the way to do that. Simply putting the caricatures on the door does not necessarily invite discussion."

The faculty union says it supports March's decision to talk about the cartoons in his class.