A cyclist suffered life-threatening injuries Wednesday evening, after police say that he rode into a Muni bus.

According to the San Francisco Police Department, the 38-year-old male cyclist struck the 6-Haight/Parnassus Muni coach at 9:40 p.m. Wednesday, as he rode through the intersection of Market and Gough Streets.

An Upper Haight reader who says he was a passenger on the bus tells SFist "The cyclist ran a red light and plowed into the rear doors... Within minutes, passers-by were calling 911 and claiming a bus hit a cyclist or the bus had run over the cyclist. The driver was horrified. Stopped traffic and muni service for the 6 and 7 came to a halt because this guy decided to run a red light."

The cyclist suffered life-threatening injuries in the collision, police say, and was transported to an area hospital for treatment.

Police do not indicate that the Muni operator or any passengers were injured in the crash. As of publication time, additional details on the wreck were not available.