Jane Longhurst's body was found five weeks after she disappeared

Initial steps were agreed by David Blunkett and US Deputy Attorney General Jim Comey during a meeting at the US Department of Justice in Washington DC.

The Jane Longhurst case had "horrified" US officials, the spokesman said.

Websites featuring extreme sexual acts were implicated in the trial of the man who murdered the Brighton teacher.

Political pressure

Musician Graham Coutts, 35, from Hove, was convicted of strangling the 31-year-old teacher and jailed for life on 4 February.

During the trial, the jury heard Coutts had strangled Miss Longhurst hours after he viewed sites which featured necrophilia and other extreme sexual acts.

We agreed it was a significant problem in terms of the evil of these sites David Blunkett's spokesman

He then kept her body in a storage unit for 35 days, during which time he visited it 10 times.

After the trial, Miss Longhurst's mother, Liz, from Reading, Berkshire, said political pressure was needed to close down the websites.

And Mr Blunkett promised to raise the issue during his visit to the US after meeting the Longhurst family in London on Thursday.

Mr Blunkett's spokesman said: "The home secretary briefed the US officials on the Jane Longhurst case and they were horrified by the details.

'Increasingly concerned'

"The Department of Justice were very interested in what we had to say and we agreed it was a significant problem, not in terms of numbers but in terms of the evil of these sites.

"We agreed that a specific group of officials would meet jointly to work out what the next stage would be.

"The deputy Attorney General said it was something they had been increasingly concerned about."

The spokesman noted the legal implications of a crackdown were "more complicated" than banning child porn, for example, because of the First Amendment in the US, which guarantees freedom of speech.

But possible action could involve work with internet service providers and credit card companies, whose services allow people to pay to access the porn on the web, he added.