Los Angeles Police officers physically removed pop star Britney Spears from her home early today, placing the troubled celebrity on a "mental health evaluation hold," authorites said.

More than a dozen motorcycle officers and a Los Angeles Fire Department ambulance swept through the front gates of Spears' hilltop Studio City residence shortly before 1 a.m., as a police helicopter hovered overhead. At 1:08 a.m., officers inside the home radioed to commanders that "the package is on the way out."

Spears was rushed from a side entrance of her home into an ambulance. As she was driven down Coldwater Canyon Boulevard, her vehicle was escorted by more than a dozen motorcycle officers, two cruisers and two police helicopters. Her final destination was the UCLA Medical Center, authorities said.

This is the second time in a month that Spears has been placed on a 72-hour welfare hold. The first occurred on Jan. 3, when Spears declined to give up custody of her children to ex-husband Kevin Federline.

The Summit, the winding street on which Spears lives in Studio City, was jammed with the vehicles of journalists and photographers for several hours prior to the police operation.

Authorities said the welfare hold was prompted by a telephone call they received from Spears' psychiatrist. It was unclear exactly when they had received the call, but it was apparent that the operation had been carefully planned over a period of time. Unlike the first welfare hold — in which Spears' ambulance was closely pursued by a throng of photographers — vehicles today were blocked from following the same route. The motorcade that whisked Spears to the hospital also showed a large investment in resources. The line of emergency vehicles stretched longer than a football field.