A couple standing on a busy Hayes Valley corner was attacked Monday night, by an assailant police have yet to track down.

The San Francisco Police Department says the attack occurred at 8:30 p.m. Monday, at the corner of Hayes and Octavia Streets.

A 33-year-old man and a 30-year-old woman were approached by the male suspect, who police says "made a comment."

When the male victim responded, police say the suspect "started a physical altercation" with the victim. Eventually, the suspect pulled out "a tool" and stabbed the man, according to the SFPD. He then fled.

The victim was transported to an area hospital for treatment of his injuries, which police say are not life-threatening.

The suspect was last seen running east on Hayes, toward Gough Street. As of publication time, police say that no arrests have been made in this case and the suspect remains at large.