Mayor Bloomberg's Conference on Guns Today

The event, which is being co-hosted by Mayor Thomas Menino of Boston, is just one strategy in Mr. Bloomberg's arsenal for cracking down on illegal guns.

Since starting his second term, the issue has been front and center for him. He has testified in Washington against legislation restricting civil use of a gun tracing database. Most recently he has created a new police task force to deal with all gun arrests with the goal of getting a better handle on how the weapons get into the city.

Mayors from Philadelphia, Trenton, Milwaukee, Dallas, Washington, D.C., and a number of other cities are all scheduled to attend the day-long event. It will include a morning symposium and a panel of "leading experts" on gun crimes.

Mr. Bloomberg is hoping the new coalition will leverage its combined force against federal legislation and what they call lax gun laws around the nation.

Gun control proponents, including those at the Brady Campaign to Prevent Gun Violence, have lauded Mr. Bloomberg and said he is fighting a noble cause. Second Amendment advocates say he is going too far.

Author John Lott, who wrote "More Guns Less Crime," said the mayor is wasting his time because gun control does not lead to reduced crime. The problem, he said, is that gun control measures too often disarm law-abiding gun owners and not criminals. "At best it doesn't work," he said. "And at worst it can be counterproductive."