Baby assaulted on San Francisco bus, police say

San Francisco police are looking for a man who allegedly assaulted an infant on a city bus on Friday, officials said. 

The baby was with its father on a Muni bus when "an unknown male subject approached the infant and physically assaulted the infant without any provocation," San Francisco police said.

The infant was not injured, police said. Police did not specify how the man assaulted the baby.

The man exited the bus and fled, police said. Officials did not provide a description of the man. 

The assault happened near Van Ness Ave. and O'Farrell Street at approximately 9 a.m.