A man suffered life-threatening injuries when he was assaulted and robbed at United Nations Plaza on Friday morning, police said.
At about 9:55 a.m. Friday, near the intersection of Market and Hyde streets, a male suspect allegedly punched another man in the head, police said.
The victim, a man in his 40s, fell to the ground and struck his head on the pavement, according to police.
The suspect allegedly robbed the victim, but police have not said what items were taken.
Police said the victim was rendered unconscious and transported via ambulance to San Francisco General Hospital with injuries considered life-threatening.
No arrests have been made in connection with the attack and police have not yet released a description of the suspect.