Canadian pop sensation Justin Bieber, seen performing in New York on Monday, has defended his manager over the incident. (Bryan Bedder/Getty Images)Justin Bieber has come to the defence of his manager, who surrendered to police in New York on Wednesday over a scuttled 2009 appearance that drew an unruly, frenzied throng of the Canadian teen pop sensation's fans.

Scott (Scooter) Braun has entered a not guilty plea to a host of charges, including reckless endangerment, criminal nuisance and endangering the welfare of a child.

"My mother and I are 100 per cent behind my manager," 16-year-old Juno-nominated Bieber said in a statement Wednesday night.

"He is someone of high moral character and principle. The decisions he made that day were to protect the safety of myself and my fans and I am very thankful to have someone in my life who watches over me the way Scooter does."

The arrest stems from a scheduled November 2009 autograph signing at a mall in suburban New York. As fans gathered to wait for the Stratford, Ont.-born singer, some grew wild and disorderly. Police cancelled the event.

After fans refused to leave, officers contacted James Roppo, a senior vice-president at Island Def Jam Records (Bieber's label), and the singer's manager Braun to send out a Twitter message about the event being cancelled.

An hour later, still no message had been sent and the rowdy crowd remained. Five people were later taken to hospital with minor injuries.

According to police, Braun claimed to be in a meeting without access to a computer when contacted by authorities. When informed he faced arrest, he reportedly told officers to make sure they spelled his name right.

Braun sent two Twitter messages about the event being cancelled about 90 minutes later, according to the district attorney. The crowd dispersed about 15 minutes following these Tweets.

Braun's lawyer has argued that his client responded promptly to the police requests.

Roppo was also arrested and charged with misdemeanours, including endangering the welfare of children and obstructing governmental administration.

Bieber, who initially came to fame after posting videos of himself singing on YouTube, released his first album My World in November 2009. His followup album My World 2.0 debuted this week.

With files from The Associated Press