Two mayors are leaving New York City Mayor Michael Bloomberg's Mayors Against Illegal Guns groups claiming the group is a misnomer. (Al Behrman/AP)

The mayors of Rockford, Ill., and Nashua, N.H., have decided to leave Mayors Against Illegal Guns, an advocacy group spearheaded by New York City Mayor Michael Bloomberg that pushes for new gun control laws.

Independent Mayor Lawrence Morrissey of Rockford and Republican Mayor Donnalee Lozeau of Nashua both said the group's name is misleading.

"I've dropped out of a group called Mayors Against Illegal Guns," Morrissey said at a June 22 town hall meeting, to loud applause. "The reason why I joined the group in the first place is because I took the name for what it said – against 'illegal' guns."

In Rockford – Illinois' third-largest city, with more than 150,000 residents – gun crime infrequently involves assault weapons, Morrissey said, but often involves handguns that are "usually in the hands of people who are prohibited from having them," particularly convicted felons.

Morrissey joined MAIG because "I thought it was about enforcement of [the] existing gun laws" against illegal weapons, the three-term mayor said. "As the original mission swayed, that's when I decided that it was no longer in line with my beliefs"

Lozeau, the mayor of New Hampshire's second-largest city, cited the group's attack on U.S. Sen. Kelly Ayotte, R-N.H., after she voted against legislation that would have expanded background checks to cover almost every gun transaction.

"Nowhere within the literature of this group was there any indication that there would be campaigns against members of Congress, particularly around issues that were not related to illegal guns," Lozeau said in a statement provided to U.S. News.

"I said, 'Wait a minute, I don't want to be part of something like that,'" Lozeau told the Union Leader on Monday."I told them, 'You're Mayors Against Illegal Guns, you're not mayors for gun control,'"

Although Lozeau's decision to leave was first reported this week, she says she withdrew in May. Her exit leaves the mayor of Dover, N.H., as the coalition's only Granite State member.

The website of Mayors Against Illegal Guns lists more than 900 members, representing large and small cities alike. The group is co-chaired by Bloomberg and Boston Mayor Thomas Menino, a Democrat. MAIG launched in 2006, but has gained significant public attention pushing for new laws after the December 2012 Newtown, Conn., elementary school massacre.

"Mayors have occasionally chosen to leave the coalition, but our growth has always far outpaced the number of mayors who have departed," the organization said in a statement provided to U.S. News. "We thank Mayors Morrissey and Lozeau for their time with Mayors Against Illegal Guns and we wish them all the best."

Last week the group was forced to apologize after memorializing accused Boston bomber Tamerlan Tsarnaev as a victim of gun violence during a rally in Concord, N.H. Protesters and counter-protesters clashed at the rally, which was part of MAIG's "No More Names" bus tour. As a list of gun victims was read, one counter-protester shouted "he's a terrorist!" when the Chechen immigrant's name was read.

Tsarnaev "was absolutely not a victim, his name should have been deleted before the list was provided to a family member for reading and his name should never have been read," said the group in a statement. "It was a mistake, it should not have happened and we sincerely apologize."