Detectives were last night hunting a serial armed robber believed to be behind six robberies within a week.

The search was under way for the man thought to have struck repeatedly in St Leonards since November 26.

The latest robbery took place at 2am yesterday when a khaki green bag containing a phone and purse was snatched.

Extra officers have been drafted in to aid the investigation, house-to-house inquiries are taking place and CCTV footage is being examined.

Police said the strikes have been centred on the Marine Court area of the seafront.

Detectives said information suggested the black suspect was living in the area with a white woman. Detailed descriptions were yesterday issued as police urged the public to contact them with information.

Detective Inspector Tim Nunn said: "This is a very worrying series of robberies which have left a number of victims deeply shocked.

"I would appeal particularly to people living in the Marina area to consider the descriptions and whether anyone fitting them lives near to them."

In the first robbery, a black man escaped with £200 after a cashier at Threshers off-licence in the Marina was threatened at knifepoint.

The second robbery, at 8.50pm on November 30, involved a taxi driver being robbed of a cash bag containing £75. A woman called a taxi firm and arranged a pick up from the Marina. When the taxi arrived, a black man got into the front passenger seat and asked to go to West Hill Road, where the robbery took place.

The third incident was last Thursday and again involved a taxi driver.

A woman arranged for a taxi to collect her outside Victoria Court, Marina, but in Archery Road a black man got in and threatened the driver with what appeared to be a screwdriver.

The driver handed over his money bag containing about £35 and the man fled up an alley that leads to the church in Undercliff.

The fourth offence was at 11.15pm on Friday at the entrance to Marine Court when the victim placed a cash box on the floor to phone his girlfriend to let him in. A black man appeared behind him and threatened he had a knife before stealing the cash.

In the fifth robbery, at 3.45pm on Saturday, a black man entered Marina Newsagents brandishing a sharp implement at the cashier and fled with £300 cash from the till.

At 2am yesterday a black man snatched a bag containing a phone and purse from a man and woman walking along the Marina.

Detective Sergeant Geoff Childs said the suspect is about 6ft, around 30, with short dreadlocks, and could have stubble or a beard.

His female accomplice is white, 5ft 2in to 5ft 5in, aged 19 to 22, with brown, scruffy shoulder-length hair.

Anyone with information should call Sussex Police on 0845 6070 999.