A 54-year-old man is in critical condition after being struck by a CTtransit Bus on Glenbrook Road on Thursday, police said.

It happened around 5 p.m.

Police said the man, a Stamford resident, suffered serious injuries and is listed in critical condition.

The bus driver, 50, immediately called for help after the crash and remained on scene, according to police.

Police are investigating, but initial reports say the man may have fallen from the sidewalk into traffic and the path of the bus driver.

Anyone who may have witnessed the crash is asked to contact the Collision Analysis and Reconstruction Squad at 203-977-4712.