The carjacking was reported at about 5 a.m. Tuesday near Second and King streets.
The 28-year-old driver was flagged down by a suspect who got into the cab and ordered the driver at gunpoint to get out of the car, according to police.
The suspect, a man in his 20s, then got into the driver's seat and drove away. He had not been found as of this morning, police said.
Anyone with information about the carjacking is asked to call the Police Department's anonymous tip line at (415) 575-4444 or to send a tip by text message to TIP411.
