SAN FRANCISCO (CBS SF) – A man was seriously injured in a stabbing outside a bar in San Francisco’s Cow Hollow neighborhood early Sunday morning.

The stabbing was reported at 1:06 a.m. Sunday in the 3000 block of Buchanan Street, near Union Street.

READ MORE: 49ers Fans Look to Make Noise, Boost Team at NFC Championship Game

The incident started between patrons who had just exited a bar. The altercation escalated and a man with a knife stabbed the victim, who is in his early 20s, police spokeswoman Officer Tracy Turner said.

The victim was taken to San Francisco General Hospital with stab wounds that are considered life-threatening, according to police.

READ MORE: Solo Crash Friday Night Closes Moraga Road, Cuts Power to Hundreds

The suspect fled and had not been found as of Wednesday afternoon. He was described as a white man between 20 and 30 years old who is about 6 feet tall and weighs about 200 pounds, Turner said.

Anyone with information about the stabbing is encouraged to call the Police Department’s anonymous tip line at (415) 575-4444 or send a tip by text message to TIP411 with “SFPD” in the message.

MORE NEWS: S.F. Supervisors Set to Designate Casa Sanchez Bldg. in Mission District a Historical Landmark

(Copyright 2013 by CBS San Francisco and Bay City News Service. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)