Craigslist recently toppled MySpace as the most visited site

The boss of classified adverts website Craigslist says the firm is being unfairly targeted by US prosecutors over its adult listings.

The attorney general of South Carolina has threatened to sue the firm for continuing to have "advertisements for prostitution and pornographic material"

Last week, Craigslist said it would eliminate its erotic services category and screen all adult services adverts.

Craigslist boss Jim Buckmaster said he was being "publicly condemned".

In a blog post, Mr Buckmaster said: "South Carolina Attorney General, Henry McMaster, today announced that our recent improvements, which go far beyond measures he himself personally endorsed with his own signature six months ago, not only aren't good enough, but actually require a criminal investigation.

"He evidently feels justified in singling out Craigslist for investigation, and publicly condemning me personally as being worthy of criminal prosecution."

Mr Buckmaster said there were a greater number and more explicit adult adverts available on other websites and publications in South Carolina.

'No alternative'

It follows Mr McMaster's assertion that the site still contained advertisements for prostitution.

The attorney general said: "We have no alternative but to move forward with criminal investigation and potential prosecution."

Craigslist was in the headlines last month after a Boston-area man was accused of fatally shooting a woman, Julissa Brisman, 26, who placed an ad on the site.

Police believe 22-year-old Philip Markoff may have been involved in other crimes against women who also posted advertss on the site.

The case was widely covered in the media, with Mr Markoff being dubbed the Craigslist Killer.

Craigslist was started in 1995 as a hobby by Craig Newmark, who put together an e-mail list of events happening in San Francisco.

Today, the firm employed 28 people working out of San Francisco, although Buckmaster says his priority is making users' lives easier, not making money.

Forty million adverts are posted on Craigslist each month.