Justin Bieber was detained by customs officials at Los Angeles' LAX Airport on Thursday (April 24) for three to four hours.

The singer had been returning to the US after visiting Asia and it is unclear why the 20-year-old was detained, although it is suggested that his pending criminal cases were flagged up.

A spokesperson told the Hollywood Reporter that Bieber has since been released after hours of questioning.

The news meanwhile came after the 'Believe' singer successfully got his impending DUI trial date delayed.

The singer, who was arrested in Miami earlier this year by cops after apparently drag racing, was due to face trial on May 5.

However, it has now been moved to July 7 so that his legal team can examine evidence and decide whether to accept a potential plea deal.

Watch Justin Bieber's 'Confident' video below: