03/18/2015 04:45 EDT | Updated 05/18/2015 05:59 EDT

Police rescue underway in Lac Saint-Louis

Police are trying to rescue a man who has somehow ended up in Lac Saint-Louis, in Lachine.

It remains unclear how the man ended up in the water.

Firefighters said witnesses called 9-1-1 at around 1:30 p.m. to report they saw a man, walking along the lake's icy shore, fall into the water.

However, police said witnesses told them the man was running.

“Did the ice give way? Did the mean slip off the edge and into the water? That’s not clear," said CBC reporter Jay Turnbull from the scene.

Two witnesses being treated for nervous shock

Police boats and divers remain at the scene.