The South Carolina attorney general engaged in a verbal and legal battle with Craigslist over possible prostitution-related charges said Thursday he has never handled a single such case in more than six years as the state's top prosecutor.

"I don't think this office has handled any prostitution prosecutions ever," Attorney General Henry McMaster, who was first elected in 2002, told The Associated Press Thursday. "Now this is something different. This is against the biggest want ads Web site in the world."

McMaster, a Republican expected to run for governor in 2010, has garnered headlines by saying he would go after the Internet advertising company for aiding and abetting prostitution if the site leads to a prostitution case in South Carolina.

Last year, Craigslist pledged to McMaster and dozens of other attorneys general that it would implement safeguards, like allowing users to flag pornographic postings they think violate the Web site's rules. But McMaster said those measures weren't enough.

The war of words reignited May 5, when the attorney general called on CEO Jim Buckmaster to remove ads related to prostitution and pornography from its South Carolina sites, giving the San Francisco-based company 10 days to comply or face possible charges.

Craigslist subsequently pledged to eliminate its "erotic services" category and screen submissions to a new "adult services" section before posting them. But when the deadline expired May 15, McMaster said he still intended to charge Craigslist executives with aiding and abetting prostitution if an ad on the Web site leads to a prostitution case in South Carolina.

Ann Bartow, a professor of Internet law at the University of South Carolina School of Law, said McMaster's decision to take on Craigslist and not local newspapers that advertise escort services suggests political motivations.

"Why Craigslist? Newspapers run the same ads, but they have people locally who would stand up for them, and he didn't want to alienate the newspapers that would be reporting on his campaign," Bartow said.

Buckmaster suggested much the same thing earlier this week on his blog, saying McMaster has gone after his company, and not other publications that also advertise sex services, for political reasons.

"craigslist may not matter in your world view, despite our popularity among your constituents, but mightn't you want an endorsement from any of the SC newspapers for your gubenatorial campaign, whose publishers you've just labeled as criminals?" Buckmaster wrote.

But McMaster insists that he has targeted Craigslist at the behest of local law officers who say it's the No. 1 marketplace for adverting sex services.

"It is the vehicle of choice for prostitution in this country, and they had been notified emphatically that those were prostitution ads," McMaster said.

After demanding an apology from McMaster for targeting his company, Buckmaster on Tuesday filed a federal lawsuit against the prosecutor, claiming McMaster's threat to file charges against the company violates executives' constitutional rights. The complaint also seeks a restraining order to prevent McMaster from filing any such charges. It also names the state's 16 solicitors, calling them McMaster's agents throughout the state.

Buckmaster declined to comment on the continuing investigation Thursday.

McMaster says his office is continuing the investigate the ads in the new "adult services" section, but no charges have been brought. In South Carolina, the charge for aiding and abetting prostitution carries a fine of up to $3,000, at least one year in jail, or both, on three or more convictions.

McMaster has said any possible charges against Craigslist would arise only after an investigation first by local law enforcement. That's the same stance he took in 2007, when a state lawmaker asked McMaster to determine if prosecution were warranted over ads for escort services in the telephone book.

"Any such determination ... would be a factual decision for local law enforcement and/or the local solicitor's office," McMaster wrote. "Such would have to be determined on a case by case basis."