A semi truck and two passenger vehicles have crashed on Highway 93, causing an explosion that engulfed all three vehicles in flames and claimed the lives of an unconfirmed number of people.

Mounties say the collision occurred in Kootenay National Park at around 3 p.m., and that the driver of the large truck was the only survivor.

The number of occupants in the other two vehicles and their identities is unknown.

The fire has been contained to the vehicles and highway and does not pose an immediate wildfire threat.

More information on the crash and victims is expected later Friday night.

Highway 93 will be closed indefinitely.

Do you have pictures or video of this crash to share? Email bcassign@ctv.ca