Five people were hurt in collisions with motorists who fled the scene this weekend, at least one of them left with injuries police say are life threatening.

The first crash, says the San Francisco Police Department, went down Saturday at 5:27 p.m. at Valdez Avenue and Monterey Boulevard.

A 64-year-old woman and a 65-year-old man were crossing the street, police say, when an unknown driver "struck both pedestrians and fled."

The female pedestrian was left with life-threatening injuries, police say, while the man's were less serious. Both were transported to San Francisco General Hospital for treatment.

Three more people were injured in a second collision late Sunday night/early Monday morning. According to the SFPD, a vehicle that contained three people "failed to stop at a red light" at the intersection of Third and Mission Streets at 1:20 a.m. Monday.

As the driver ran the light, they collided with collided with a second vehicle, then spun out and struck a pedestrian on a nearby sidewalk.

The three people from the suspect vehicle then exited the vehicle and fled the scene on foot in an unknown direction, police say.

Two passengers in the vehicle they struck — a 39-year-old man and a 42-year-old man — were injured in the collision, as was the 43-year-old female pedestrian. All three were transported to San Francisco General Hospital.

In both cases, police say, the hit-and-run drivers remain at large, and no arrests have been made in either collision.

Related: Errant SoMa Parker Turns Pedestrian Collision Into Hit-And-Run