Julio Camera has paparazzi pinned on ground

Britney Spears has allegedly broken the terms of her custody agreement by taking her sons to Las Vegas without Kevin Federline's permission.The 'Toxic' singer - accompanied by her brother Bryan - flew by private plane to America's gambling capital on Wednesday afternoon with 22-month-old Sean Preston, and 10-month-old Jayden James and checked into the Wynn Las Vegas hotel.Under California law, neither parent is allowed to take a child out of the state without written permission from the other - or by obtaining a court order. A source told Us Weekly magazine: "Kevin is demanding she get back to Los Angeles because she isn't allowed to have the kids out of state."Britney did not have written permission and she needs this to take her children out California. She never got it or alerted people she was leaving.I'm sure Kevin's lawyer, Mark Vincent Kaplan, is mulling over how to handle this."Britney had checked out of the Wynn by 5.30pm Las Vegas time on Thursday but not before causing some drama. Eyewitnesses claim the 25-year-old singer's bodyguard, Julio Camera, attacked a photographer outside the Wynn Spa after an argument over the lensman being too close to Sean Preston. One photographer claims Camera shoved his partner in the chest and accidentally hit toddler Sean Preston in the process.The photographer then alleges Britney started yelling while Camera tackled his partner to the ground and began punching.Sergeant Loretto of the Las Vegas Police Department said Camera has been issued a citation for misdemeanour battery. Loretto added: "A second Incident Crime Report was also filed by Ms. Spears on behalf of her minor child. In that report it was alleged that prior to the above incident a second photographer, identified as Kyle Henderson, battered both Mr. Camera and Ms. Spears' child, who was at that time being held by the security officer."