A man crossing a San Francisco street was seriously injured Monday, when a driver struck him then sped away from the scene.

Police say that the 77-year-old male pedestrian was crossing near the 2000 block of McKinnon Avenue at 7:38 p.m. Monday, when he was struck by an unidentified driver.

As of Tuesday morning, it was unclear where on the block the pedestrian was crossing, and if the pedestrian was crossing at a controlled intersection or in a crosswalk. Police also did not have any details on the driver or vehicle involved in the crash, just that he or she "fled scene."

According to the San Francisco Police Department, the victim was left with life threatening injuries, and was transported to San Francisco General Hospital for treatment.

The crash is being investigated by SFPD's Traffic Collision Investigation Unit, police say. If you have any information on the hit-and-run, you're urged to call them at (415) 553-1641, the Anonymous Tip Line at (415) 575-4444 or to Text A Tip to TIP411 and begin the message with SFPD.