Mayors are leaving New York City Mayor Michael Bloomberg's gun-control group, Mayors Against Illegal Guns, saying they feel misled by the original purpose of the group and are concerned about the direction in which it's heading.The organization has lost 50 members in the last five months, although the group's membership has grown overall. Many say they left the group because its initial mission has changed from being against illegal guns to opposing those who support gun rights,Mayor Donnalee Lozeau of Nashua, N.H., said she was bothered by the television ads the mayors' group launched against Republican Sen. Kelly Ayotte of New Hampshire when she voted against the gun bill in the Senate that aimed at expanding background checks on gun purchases."I said, 'Wait a minute. I don't want to be part of something like that,""I told them, 'You're Mayors Against Illegal Guns, you're not Mayors for Gun Control.'""Nowhere within the literature of this group was there any indication there would be campaigns against members of Congress, particularly around issues that were not related to illegal guns," she added.Rockford, Ill. Mayor Lawrence Morrissey expressed similar sentiments that led him to quit Bloomberg's illegal-gun group."The original focus, I thought, was going to be on focusing on better enforcement of our existing laws, and if anything, we have talked about not getting involved with things like banning assault weapons and banning magazine clips,"about why he quit in June.A number of mayors aren't on the original list from early February because they resigned their post or lost an election, but others requested to be taken off the group's membership list, according to Buzzfeed.Democratic Sen. Chuck Schumer of New York expressed frustration recently when Mayors Against Illegal Guns started targeting Senate Democrats in red states who hold seats that are already vulnerable."The mayor of New York City is putting ads against people in red states is not going to be effective," Schumer said.Even though some mayors have left the group, the gun group's membership shot up drastically over the last year."Membership has actually increased by more than 50 percent from one year ago," said Bloomberg spokesman John McCarthy. "We now have more than 1,000 mayors in coalition nationwide, compared to 650 last year."