The Los Angeles Times said the 19-year-old singer bumped into the unidentified photographer as he was leaving the hotel, prompting the photo-snapper to yell, "That's assault" -- and then unleashing a string of profane insults at Bieber as he was getting in his car.
The entertainer then turned back from his vehicle and threatened to beat up the offending photographer before members of Bieber's entourage dragged him back to his car, the Times said.
"Ahhhhh! Rough morning. Trying to feel better for this show tonight but let the paps get the best of me... ," Bieber tweeted Friday morning. "Sometimes when people r shoving cameras in your face all day and yelling the worst thing possible at u...well I'm human. Rough week. Not gonna let them get the best of me again. Gonna get focused on this show tonight. Adrenaline is high now. Gonna put it on the stage. Only way someone can break u is if u let them."
Bieber was briefly hospitalized Thursday night after he collapsed with breathing problems offstage at his concert at London's O2 Arena. He played his last of four shows at the venue Friday night.