One of the members of Mayor Bloomberg’s anti-gun coalition has pleaded to charges of illegally carrying a gun into a church, onto a college campus, and into a park.

The mayor of Jackson, Miss., Frank Melton, is one of more than 100 mayors in the coalition Mr. Bloomberg and the mayor of Boston, Thomas Menino, created to push for stronger gun control laws.

But, last week, Mr. Melton — who according to news reports, carries firearms at all times and has a reputation for being tough on crime — pleaded no contest to carrying a concealed gun on the campus of a Mississippi College School of Law. He also pleaded guilty to carrying a gun into a church and into a park, also illegal under state law. The first was reduced from a felony charge to a misdemeanor; the latter two were misdemeanors.

Yesterday the National Shooting Sports Foundation, a firearm industry trade group, called on Mr. Bloomberg to insist on Mr. Melton’s resignation.

“I write to inquire whether you, as co-founder of the Mayors Against Illegal Guns coalition, will follow the lead of the firearms industry and demand Mayor Melton resign from public office?” the letter said. “Will you at least take the internal steps necessary to bar Mayor Melton from participating in your coalition?”

A spokeswoman for Mr. Bloomberg, Virginia Lam, called the National Shooting Sports Foundation letter a “publicity stunt.”

“No one is above the law,” Ms. Lam said, “but instead of mounting a public relations campaign to take down a tough opponent of illegal guns, the NSSF should be working with us to help keep illegal guns out of the hands of criminals.”

Ms. Lam declined to say if Mr. Bloomberg had talked to the Jackson mayor, but said Mr. Melton was still invited to a planned conference the coalition is holding in January in Washington, D.C.

“Mayor Melton has been an important member since the beginning and we look forward to his continued contribution to the coalition,” she said via e-mail.

The Mississippi attorney general, James Hood, was considering having Mr. Melton resign as part of a plea agreement, but the final deal included six months of probation instead and a $1,500 fine.

Mr. Melton still faces a batch of felony charges centered on accusations that he ordered a group to destroy a duplex with sledgehammers because of the drug problem there. Calls to Mr. Melton’s office were not returned yesterday.