(CBS/AP) Thousands of "tween" girls jammed a vast square with their parents in Mexico City on Monday night, screaming in unison throughout a free concert by teen superstar Justin Bieber.
Bieber opened the show, an event that was expected to draw 200,000 people to the historic center of Mexico's capital, with his hit song "Baby," while his adoring fans filling the city's main plaza sang along or shouted "Justin! Justin! Justin!"
"Mexico City, there is a lot of people today!" Bieber told the crowd. "Every one of you is my biggest fan."
Dressed in white jeans and a gray sweatshirt that he took off to reveal a white T-shirt, the 18-year-old singer wore neon yellow tennis shoes and was accompanied by five dancers in neon colors. Four giant screens showed parts of his music videos to the crowd of mainly girls and their parents, who braved a light, intermittent rain during the concert.
The crowd went wild when Bieber asked a fan onto the stage, gave her a bouquet of flowers and sang "One Less Lonely Girl" into her ear. The girl didn't stop crying.
The gray 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 favorite color.
After singing a couple of songs while playing an acoustic guitar, Bieber changed into an all- black outfit and sang some of his more energetic songs, including "Somebody to Love."
The two-hour concert, which opened with Mexican pop group 3Ball MTY and "Call Me Maybe" singer Carly Rae Jepsen, closed with fireworks and confetti spewing from the stage.
At a news conference before the concert, the teen star said there is no artist alive that he would spend days in line 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 honored," Bieber said.
Hundreds at the Zocalo, which was filled to capacity, had to cover themselves in plastic rain capes sold by vendors who came prepared for a rainy evening.
Earlier, girls shuffled 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 expected to watch on giant TV screens erected on nearby streets.
Authorities said they would have more than 5,000 police on hand, partly to prevent the sort of crush that injured 40 Bieber fans at a free concert in Oslo, Norway, in late May.
"Most of the fans will be between 10 and 17 years old. There will be a lot of girls," said Hector Antunano, a city official. "We are being very careful that the majority of the police are women and we are taking precautions so that there is no rush toward the stage."
A similar concert in the Zocalo last month by former Beatle Paul McCartney drew an estimated 230,000 people, including President Felipe Calderon. There was no word on whether the president took his children to see Bieber.