Two visitors to San Francisco were robbed and a third knocked out during a violent morning mugging on Twin Peaks Boulevard yesterday.

According to the San Francisco Police Department, it was 11:15 a.m. Monday when a 50-year-old and a 77-year old female tourist and an 81-year-old male tourist, all carrying French passports, were taking pictures on the 100 block of Twin Peaks Boulevard, which is near Tank Hill Park.

They trio were approached by two men between the ages of 20-25, one of whom demanded the 50-year-old woman's property, police say. Even though she handed it over, the men still shoved the male tourist "to the ground, causing him to lose consciousness," police say.

The men then took the purse from the third tourist's shoulder, then fled the scene with the trio's camera and lens, their passports, and an unknown amount of cash.

The 81-year-old man was transported to the hospital for treatment of an abrasion to his head, loss of consciousness, and wrist pain, He is expected to recover.

As of Tuesday morning, police did not have any additional information on the suspects, but did say that no arrests had been made.

As always, police say, anyone with information about the mugging is encouraged to call SFPD's anonymous tip line at 415-575-4444 or to text a tip to TIP411 with "SFPD" in the message.