ATLANTA -  A $400 million lawsuit claiming New York Mayor Michael Bloomberg libeled a Georgia sporting goods store by calling it one of several "rogue gun dealers" must be returned to the state court where it originated, a federal appeals court ruled Friday.

The decision by a three-judge panel of the 11th U.S. Circuit Court of Appeals was the latest development in a two-year legal battle that began when Bloomberg sued 15 firearms brokers in five states, including Georgia. The suit said they were selling weapons that ended up in the hands of New York criminals.

Former U.S. Rep. Bob Barr, a National Rifle Association board member representing Adventure Outdoor Sports in Smyrna, Ga., argued before the appeals court in September that the libel suit against Bloomberg and Police Commissioner Ray Kelly should be returned to state Superior Court in Cobb County, where he originally filed it.

Bloomberg's lawyers wanted the case dismissed or to remain in federal court, because it applies to whether the gun stores violated federal laws.

The mayor's lawyer, Peter Canfield, argued that the mayor has immunity under New York law for remarks made in his capacity as an elected official. But Barr countered that even though the comments were made at a news conference in New York, a weaker Georgia law on immunity should apply.

A federal judge had concluded that a Georgia law meant to discourage lawsuits aimed at stifling legitimate public discourse did not apply. New York officials appealed.

The panel instructed the lower court to "to remand this case to the state court from which it was removed."

Bloomberg's 2006 lawsuit cracking down on gun dealers eventually grew to include 27 shops. Many have settled with the city. Four have shut down and three have persuaded the city to drop them as defendants.

The owner of a South Carolina gun store also claimed slander but later dropped the suit.