Police are releasing a few more details about a hit-and-run collision that seriously injured a pedestrian in downtown Calgary on the weekend.

The Calgary Police Service does not have a vehicle description and has not been able to find the driver, so officers are hoping for tips from the public.

Officers believe the vehicle has "significant damage" to its hood, windshield and front.

CPS investigators believe a vehicle fled south on Second Street after striking a pedestrian at the intersection with 15th Avenue S.W. on Sunday. (Google Maps)

At about 2:55 a.m. on Sunday, two men crossed Second Street S.W. from east to west on the south side of the intersection with 15th Avenue S.W., police said in a statement issued Monday morning.

Police allege a vehicle failed to yield and hit the 50-year-old man, who was thrown across the road.

The vehicle then fled the scene, police said, by heading south on Second Street S.W.

Police are asking that any witnesses or people who know where the vehicle is call 403-266-1234 or Crime Stoppers at 1-800-222-8477.