A man was critically injured after being punched in Washington Square Park in North Beach on Thursday, police said.
The 35-year-old victim was drinking with some friends in the park about 8 p.m. when another man, who appeared to be in his 20s, punched the victim and knocked him out.
The victim was reportedly unconscious for one to two minutes, police said. He was taken to the hospital with injuries considered to be life threatening.
He reportedly sustained internal bleeding in his head and a skull fracture.
There has been no arrest in the assault.