Britney Spears spent the day driving around Los Angeles

Jamie and Lynne Spears said they were "extremely disappointed" that their daughter had been released against the recommendation of her psychiatrist.

Spears, accompanied by private security guards, slipped out of the UCLA Medical Center a week earlier than expected.

She had been undergoing psychiatric evaluation since 31 January.

We are deeply concerned about our daughter's safety and vulnerability Jamie and Lynne Spears

After her release, Spears spent the day driving around Los Angeles with an unidentified man, accompanied by paparazzi who surrounded the vehicle at each stop.

In a joint statement, her parents said: "We are deeply concerned about our daughter's safety and vulnerability and we believe her life is presently at risk.

"We ask only that the court's orders be enforced so that a tragedy may be averted."

The star's low-key departure from the UCLA Medical Center, in stark contrast to her admission, required no police escort, the commander of the North Hollywood police station said.

"There was no media, no paparazzi, and no need for public safety protection," Capt Sharyn Buck told the Associated Press.

More than a dozen LAPD officers escorted Spears to the facility in a motorcade on 31 January, when she was admitted to hospital and held for a 72-hour evaluation.

Restraining order

Her stay was then extended for a further two weeks, according to reports.

This week, Spears's manager was banned from going near her after a court issued a restraining order.

Lynne Spears told a judge that Sam Lutfi drugged her daughter, cut off her phone lines and called her an "unfit mother" in an attempt to take control of her life.

The 26-year-old singer was briefly hospitalised earlier in January after refusing to surrender custody of her two sons in a police stand-off.

Sole custody of the children was subsequently awarded to her former-husband, Kevin Federline.

Spears remains under the temporary conservatorship of her father until 14 February, an arrangement put in place when a judge determines a person can no longer care for themselves.

Jamie Spears has been named her conservator, and he and lawyer Andrew Wallet were made co-conservators of the estate.