A witness watched in horror as a 64-year-old woman was beaten unconscious in the Outer Sunset on Tuesday, cops said.

A wicked woman in her 30s carried out the vicious assault in the 2200 block of 48th Avenue around 10 p.m.

The witness saw her punching and kicking the victim and broke up the fight, police said. The suspect fled in a blue 2000 Ford van. No arrest has been made.

The victim was transported to San Francisco General Hospital for injuries that were not life threatening.

The motive for the attack was not immediately known.

rnagle@sfexaminer.com