Detectives were already investigating the deaths of three women, whose naked bodies were found a few kilometres apart. One body was found in a stream, another in a pond and a third in the woods, about 30 metres from a road.

The two bodies discovered Tuesday were laying near Levington, Suffolk, a village about eight kilometres south of Ipswich. The corpses of the five dead women have all been found within a few kilometres of Ipswich.

The killing has stirred memories of the so-called Yorkshire Ripper, one of Britain's worst serial killers. Peter Sutcliffe admitted to killing 13 women, mostly prostitutes, in the 1970s. He was sentenced to serve a minimum of 30 years in prison.

His reign of terror in turn recalled Jack the Ripper, the notorious Victorian serial killer who murdered at least five East London prostitutes in 1888. He was never caught and speculation about his identity continues.

The latest deaths have drawn intense media interest, with Ipswich's afternoon newspaper labelling the prostitutes' killer "the Suffolk Strangler."

Police said they suspected a serial killer in the Suffolk cases, but were not ruling out multiple suspects. Police said there was also no indication women other than prostitutes were targeted.

The three victims who have been named were identified as Gemma Adams, 25, whose body was found Dec. 2; Tania Nicol, 19, whose body was found Friday; and Anneli Alderton, 24, whose body was found Sunday. Police said Ms. Alderton, who was last seen on a train, was asphyxiated. It appeared she had been strangled and that she was not sexually assaulted, police said.

The condition of the bodies of Ms. Adams and Ms. Nicol, both of whom were found in water, has prevented investigators from determining a cause of death or whether they were sexually assaulted.

Ms. Nicholls, 29, was last seen Dec. 5; Ms. Clennell, 24, was last seen Sunday. The women, both prostitutes, were seen in the neighbourhood in the shadow of the town's soccer stadium where sex workers ply their trade.

Police were reviewing closed-circuit television video of the small district and other areas of Ipswich, which is about 112 kilometres northeast of London.

Ian Hunter, 46, who works for telecoms company BT, one of Ipswich's main employers, said that he had been fishing on Sunday in the area where Ms. Alderton was found.

Ipswich, a town of about 120,000, is normally "pretty relaxed," Mr. Hunter said, but the murders have set residents on edge.

"My daughter is 13, and once a month, they have a youth club (in town). And she won't go," Mr. Hunter said. "There's supposed to be one this Friday, but she won't go.

"My wife works in town, and they've been told to only move about after dark with a friend."

Prime Minister Tony Blair voiced his shock Wednesday at the mounting scale of the scare, which has seen five naked women's bodies found within the space of 10 days in farmland and streams around Ipswich.

"We support the police fully in dealing with this horror," said Blair as the affair dominated the start of his weekly quizzing in the House of Commons in London. Opposition Tory leader David Cameron called the killer a "monster."

In Ipswich itself, the detective in charge of the inquiry said he feared that the latest two bodies found on Tuesday "may well be" those of two missing prostitutes, 24-year-old Paula Clennell and Annette Nicholls, 29.

Their deaths would add to those of three other sex workers already confirmed as murdered: Gemma Adams, 25, 19-year-old Tania Nicol, and 24-year-old Anneli Alderton.

"I now fear the worst," said Detective Chief Superintendent Stewart Gull, giving an update on the latest developments.

Police have so far refused to confirm categorically that they are dealing with a serial killer -- but Gull admitted again that signs increasingly point that way.

"Clearly there are some striking similarities between these five" killings, he said.

The case has evoked thoughts of one of the country's most notorious serial killers, east London's elusive Jack the Ripper, who murdered five prostitutes in 1888 and was linked to several other killings.

They have also revived more recent memories of Peter Sutcliffe, the "Yorkshire Ripper", who preyed on prostitutes and murdered 13 women and attacked seven others between 1975 and 1980.

All the corpses have been found in the countryside around Ipswich, some 80 miles (130 kilometres) northeast of London, prompting one of Britain's biggest ever murder inquiries.

"This is a most unprecedented inquiry. Nothing like this has ever happened," said Alastair McWhirter, head of Suffolk Police, noting that the Yorkshire Ripper murders took place over a longer period of time.

The streets of Ipswich were virtually deserted overnight -- the 30 or so prostitutes who usually work the red light district seemed to heed police advice to stay indoors, while the streets were all but empty of revellers during the normally busy Christmas party season.

Pairs of police officers carried out patrols to reassure local people for the second night running, while motorists were being stopped and questioned.

Suffolk Police, a rural force more used to dealing with illegal dance raves than fast-moving murder cases, has faced questions from the media about whether it is equipped to cope.

But senior officers insist they are handling it well and have requested assistance from forces around Britain, as well as enlisting a behavioural analyst to help them understand who might have committed the crimes.

Gull, who has described the case as "almost a crime in action," confirmed that an extra 70 officers would be drafted in Wednesday to help the 100 police already working on the case.

No other prostitutes are currently reported missing.

As the probe continued, one newspaper offered a record 250,000 pound reward for information leading to the arrest of the killer.

"We hope this historic reward will help in solving the series of brutal murders which has shocked the nation," said the weekly News of the World, which is published on Sundays.

Paula Clennell, 24, has not been seen since Saturday and Annette Nicholls, 29, has been missing for at least a week.

"Three of their peers have been murdered, now tragically possibly another two. It's not safe. They need to stay off the streets," Detective Chief Superintendent Stewart Gull told BBC radio.

The discovery of so many victims in so few days has raised fears another "Ripper" targeting prostitutes is on the loose.

The most notorious such killer was the 19th-century murderer known as Jack the Ripper, blamed for the deaths of five prostitutes in east London in 1888 but never found.

The most prolific was Peter Sutcliffe, called the Yorkshire Ripper, who murdered 13 women, mainly prostitutes, in northern England from 1975 to 1980 before he was caught.

NEWSPAPER REWARD

Reinforcements have been drafted in to help the small Suffolk police force in its largest inquiry. Prime Minister Tony Blair's office said it had been in touch with police to ensure all necessary resources were available.

Police said they had received more than 2,000 telephone calls from members of the public in just five hours.

"Our number one priority is to find the person or persons responsible," said Gull.

"We are coming into the festive period and people are going to be out and about. We would advise them to take care," he told a news conference.

Gull said all five girls had been murdered elsewhere and their bodies dumped. Police were looking for the murder scenes.

The News of the World, Britain's biggest selling newspaper, offered a reward of 250,000 pounds ($490,000) for the capture of the person it dubbed the "Suffolk Strangler".

The two latest bodies were discovered in Levington, east of Ipswich, close to where the naked body of another victim, Anneli Alderton, 24, was found in woodland on Sunday.

Mike Berry, a criminal psychologist, said the Ipswich killer was an exceptionally cold-blooded and skilful operator.

"The killer may be confident he will not be caught," he wrote in the Daily Mirror. "He will be fascinated by the coverage of the case ... he will be thinking 'the game is on'."

A huge police inquiry began on December 2 when the body of Gemma Adams, 25, was found in a stream near Ipswich. Police found 19-year-old Tania Nicol's body in the same stream on December 8.

(Additional reporting by Deborah Haynes, Michael Holden, Kate Kelland and Jeremy Lovell)