Reports have emerged from the UK that fallen pop star Britney Spears tried to hang herself with a bedsheet during rehab, after screaming that she was the "anti-christ".

She made the demonic cry after scrawling the devil's number "666" across her head.

Spears's manic behaviour has concerned relatives who once again fear for her safety, and has staff at the Promises Clinic in Malibu, California struggling to cope.

The former chart-topper's troubles have been revealed in Britain's News Of the World, which broke the exclusive story.

Within days of her suicidal behaviour, Spears - who was in and out of rehab before shaving her own head and later attacking a photographer's car with an umbrella - was begging estranged husband Kevin Federline not only for a reconciliation, but demanding she wanted to soon have another baby.

The ordeal began when she terrified staff by writing the number of the beast on her head and running around the clinic screaming, "I am the anti-christ!"

"The clinic people just didn't know what to do," a friend claimed.

The pop star then tried to hang herself with a bedsheet was but was found before she could hurt herself.