The self-policed community site, which started as an email distribution list for friends, has been under pressure from US attorneys-general to remove the ads.

In May 2009, it bowed down to threats of legal action by replacing its "erotic services" section with pre-approved "adult" services listings.

The site was involved in the high-profile case of a murder of a prostitute in Boston by a man, dubbed the '"Craigslist killer", who had met her through the site.

In a blog post in August, Jim Buckmaster, Craigslist chief executive, said the site was "committed to being socially responsible" when it came to adult services ads and was currently working with "experts and thought leaders at leading non-profits and among law enforcement" on further substantive measures to ensure this.

Buckmaster said that in the year following the introduction of manual screening of adult services, more than 700,000 ads had been rejected by attorneys in the US.

"Craigslist’s posting guidelines are stricter than those typically used by yellow pages, newspapers, or any other company that we are aware of," he said.

Buckmaster accused eBay, which has a stake in Craigslist, of carrying similar listings, without vetting.

Craigslist has made no announcement on the censorship and was not immediately available for comment. There is no censorship on the erotic section on the UK version of Craigslist.