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Fans of pop star Justin Bieber cheer outside a hotel where Bieber gave a news conference in Mexico City, Monday, June 11, 2012. Bieber will perform in a free open-air concert tonight at the Mexico City's main historic plaza, the Zocalo. (AP Photo/Alexandre Meneghini)

Mexico City packed for Bieber concert

Thousands of "tween" girls jammed a vast square with their parents and screamed in unison throughout teen superstar Justin Bieber's free concert June 11, an event that was expected to draw 200,000 people to the historic center of Mexico's capital.