State attorneys general from Missouri, Illinois and Connecticut plan to begin negotiations with Craigslist to eliminate what they contend are advertisements for illegal sexual activities.

The three attorneys general will represent a group of the nation's attorneys general Tuesday at a meeting in New York City with officials from the Internet classified ad service.

Missouri Attorney General Chris Koster, a Democrat, said that investigators in his office have found several ads offering sex-for-money or seeking that type of relationship on Craigslist Web sites for the Kansas City, St. Louis, Springfield, Columbia and Jefferson City areas.

"It is blatant. It is irresponsible. It is illegal," Koster said Monday in a written statement.

Click here for photos from the "Craigslist Killer" case.

Craigslist Chief Executive Officer Jim Buckmaster issued a statement saying the company looks forward to the meeting and hopes to make progress on the issue.

The company "anticipates making further progress toward the common goal of eliminating illegal activity from Craigslist, while preserving its full utility and benefit for tens of millions of law-abiding Americans who value and depend on Craigslist's free local community services in their everyday lives," Buckmaster said.

The negotiations come amid national attention to online ads because a Boston medical student has been accused of killing a masseuse he met through Craigslist.

Phillip Markoff was arrested last month and charged with the April 14 killing of Julissa Brisman, 25, of New York, who advertised on Craigslist.

On Monday, Markoff was charged in Rhode Island with assault and weapons violations. An exotic dancer from Las Vegas told police that she was held at gunpoint by a man met through Craigslist. The dancer said the man fled when her husband came to the Rhode Island hotel room.

Markoff also been charged in a separate robbery in Boston of a masseuse that police contend Markoff met through Craigslist.

Craigslist also made headlines in October 2007 when a 24-year-old Minnesota woman was found dead after responding to a phony ad for a baby sitter.