Pop star Justin Bieber is being probed by police after allegedly headbutting a man and fighting two bartenders.
The Los Angeles County Sheriff's Department said it received a battery report allegedly involving the 22-year-old singer at around 2am on Saturday.
A witness told officers that Bieber was involved in separate altercations with two bartenders at a restaurant on Sunset Boulevard, West Hollywood.
The sheriff's department said: "The witness said he broke up the fights and asked Mr Bieber to leave. Mr Bieber refused to leave and remained at the restaurant.
"The witness stated, a few minutes later, he saw Mr Bieber arguing with a patron, when Mr Bieber suddenly headbutted the patron."
According to the sheriff's department, the witness told police Bieber left the location after his friends pulled him away from the alleged victim.
Officers interviewed the alleged victim but he refused medical attention and did not want to file a police report.
There were no visible marks on the man and detectives are continuing to gather evidence, the sheriff's department said.
The bartenders allegedly involved in the incident had left the scene and did not want to file a police report, according to the witness.
A spokeswoman for Serafina Sunset, where the alleged fight happened, denied that any of its staff were involved.
The restaurant's director of public relations Caroline McBride said: "We know very little about the alleged incident at Serafina Sunset with Justin Bieber, but we can assure you that nobody from our staff was involved, nor did we call the police.
"We always have pleasant experiences with Mr Bieber whenever he comes to Serafina."
The alleged incident comes a day after police confirmed Bieber had been accused of repeatedly punching a man at a hotel in Cleveland.
Rodney Cannon claimed he was attacked by the Love Yourself singer and his bodyguards after a Cleveland Cavaliers basketball match on June 8.Representatives for Bieber could not be reached.