Police fear a serial knife attacker may have carried out a horrific sex attack on a 26-year-old woman in central Brighton today.

Officers say the rapist could be the same knifeman wanted for a series of attacks on women in the city since October 30.

As police started a major manhunt, senior detectives warned women not to walk alone in unlit areas.

If the same man is responsible for all the attacks, he has moved up the crime ladder from attempted abduction and robbery to rape.

Police are now concerned he may take the next step up to murder.

Today's victim, an Australian visitor, was returning to her hotel room after spending the evening at the Casablanca jazz club in Middle Street, Brighton.

She was entering the Cecil House Hotel in King's Road, Brighton, at 2.12am when the attacker grabbed her from behind.

He held a knife to her throat and forced her to cross the street to a yard in Queensbury Mews.

Police say she was then subjected to a "horrendous" sexual assault before her attacker fled.

The victim ran into nearby Regency Square and flagged down passing motorists who raised the alarm.

Police mounted a huge search but there was no trace of the attacker.

Detective Chief Inspector Kevin Moore, heading the hunt, said: "We urgently need help from the public. This was a vicious attack and we need witnesses or anyone with information to come forward."

Officers have warned all women that the wanted man is dangerous and should not be approached.

Mr Moore said: "I am not scaremongering for the sake of it but we have a duty to warn people. Women should not walk alone after dusk in the city centre."

The rapist is 24 to 30, 5ft 8in tall, of mixed race and has short dark hair, and possibly facial hair. He wore a blue shirt.

Mr Moore is leading Operation Tank, an investigation into at least nine attacks, mainly on women, in Brighton and Hove.