A 68-year-old cyclist was taken to hospital with critical, life-threatening head injuries after a collision in Ottawa's Cyrville neighbourhood on Tuesday morning.

The crash between the cyclist and an SUV happened at the intersection of Cyrville and Ogilvie roads just before 10 a.m., paramedics said.

Both the cyclist and the SUV were heading west when the collision occurred, police said.

Witnesses provided first aid and monitored the unconscious man's breathing until paramedics arrived, paramedics said in a media release.

He remained unconscious as paramedics treated him at the scene and was still unconscious when they arrived at hospital.

Ottawa police are investigating.