MIAMI (AFP) - A bouncer at a Florida bar has sued Backstreet Boys singer Nick Carter for attacking and choking him, labelling the star "nothing more than a backstreet thug."

Skylar Carden, 21, filed the lawsuit on Monday in a court in the Florida Keys, alleging Carter caused "bodily injury, mental anguish, pain and suffering," attorney Mark DiCowden told AFP.

Carter was arrested on Jan 13 after he and a friend were escorted, drunk, by security personnel outside Hog's Breath Saloon in Key West.

The singer was originally shown the door due to his "unruly and disrespectful" behaviour, but he then became aggressive, beating and briefly choking Carden, according to the lawsuit.

In court, Carter pleaded not guilty and was released on US$1,500 bail (S$2,100).

He broke his silence via a message on Twitter over the weekend.

"I am human and at times it can be a struggle to balance a healthy lifestyle. I'm not perfect and for that I am sorry," he wrote.

"When we fall we have to get up and keep on walking. I hope you stay by my side and continue to walk with me."

But Carden's lawyer said that regardless of Carter's celebrity status, the singer should respect other people's rights, just like everyone else.

"Nick Carter has shown the world that he is nothing more than a backstreet thug," DiCowden wrote.

"Carter's backhanded apology in the form of a tweet was a crude attempt to control public relations and did nothing to address his remorse for the harm he caused Carden.

"No amount of fame or fortune justifies Carter's shameful and outrageous conduct. To send him that message and deter his misbehaviour in the future, we will seek punitive damages against him as allowed by Florida law."

The Backstreet Boys achieved worldwide success in the 1990s and early 2000s as teen idols, with songs like I Want It That Way, Everybody (Backstreet's Back) and Show Me The Meaning Of Being Lonely.

He has also participated in the US television show Dancing With The Stars.