US singer Chris Brown has been accused of punching a man who tried to join him as he was being photographed.
Brown, who is due in court charged with assault, was arrested on Sunday outside the W Hotel in Washington DC.
A police report said Isaac Parker attempted to get into a picture with Brown and two other people and Brown told the man: "I feel like boxing."
Mr Parker told police Brown punched him in the face. Officers said another man stepped between them and also punched 20-year-old Mr Parker.
Brown is on probation for assaulting his on-again, off-again girlfriend Rihanna in 2009 just before the Grammy Awards.
The photos of Rihanna's bruised face caused outrage among many fans. Brown pleaded guilty to one count of assault and received five years' probation.
His probation was briefly revoked earlier this year after a traffic accident. A hit-and-run charge was dropped against him, but the judge gave him 1,000 more hours of community service when he reinstated his probation.
Neither Brown's publicists nor his lawyer have commented on the latest incident.