Justin Bieber fever sweeps Mexico City

Thousands of "tween" girls and their parents packed into Mexico
City's historic main plaza, braving a light but incessant rain before a
free concert by teenage superstar Justin Bieber that was expected to
draw 200,000 people.

Bieber arrived to the Zocalo area in one of four SUVs that were escorted by a dozen police officers on motorcycles while Mexican DJs 3BallMTY played to the crowd unaware of his arrival.

The grey and reddish stones of the plaza were covered in a sea of purple as the mainly 10- to 14-year-old crowd paid homage to what is reported to be Bieber's favourite colour.

At a news conference before the concert, the teen star said there is no artist he would spend days in a queue waiting for.

"There is no one I admire so much to do something crazy, but if Michael Jackson were here, I would do it for him. So, I do understand the emotion that the girls feel and that makes me feel very honoured," Bieber said.

Hundreds at the plaza, which was jammed to capacity, had to cover themselves in plastic rain capes sold by vendors who came prepared for a rainy evening.

Earlier, girls trundled through security checkpoints with hats and umbrellas, staking claim to some of the roughly 80,000 spots allocated in the plaza itself.

An additional 120,000 or more fans were watching on giant TV screens erected on nearby streets.