"If the leadership won't come from Congress or from the White House, it will have to come from us," said New York Mayor Michael Bloomberg, who led the summit with Boston Mayor Thomas Menino.
The mayors - from cities including Washington, Philadelphia, Dallas, Milwaukee and Seattle - gathered to exchange ideas, consult with experts and promote law enforcement cooperation among their cities.
They signed a resolution to combat gun violence, and Bloomberg said they hope to come back in greater numbers for a gathering later this year. The mayors hope to eventually establish a public relations campaign to pressure the federal government and state legislatures.
Menino said he met recently with a sixth-grade class in Boston in which nine out of 10 pupils said they knew where they could find a gun. The 73 homicides in Boston last year marked the highest number in 10 years, he said.
Milwaukee Mayor Tom Barrett said: "We are the ones who get the phone calls on a bright sunny afternoon that a little girl has been shot. I want those phone calls to stop."
Bloomberg has made gun control a high priority in his second term. Crime statistics show the number of shootings this year is slightly lower than last year, but high-profile gun deaths - like that of a toddler killed by a stray bullet on Easter Sunday - continue to hold a spotlight on the issue.
Bloomberg recently testified before Congress with harsh words against a bill that would prevent authorities from sharing gun data with local governments. Some municipalities had used the information to sue gun makers and dealers.
The National Rifle Association criticized Bloomberg for his congressional testimony and called Tuesday's event "a taxpayer-funded publicity stunt."
"The mayor's answer is an elitist national campaign on the backs of law-abiding gun owners," said Chris W. Cox, the NRA's chief lobbyist. "Believe me, the rest of the country does not want Mayor Bloomberg's elitist gun policies, because they don't work."
Besides criticizing the bill that would limit data-sharing and asking cities to oppose those efforts, the mayors' resolution promises to give those who commit crimes the harshest punishment allowed and to target gun dealers who break the law.
The mayors also resolved to support legislation to fight gun crimes and to develop technology to detect and trace illegal guns.
Those attending also included the mayors of Providence, R.I.; Hartford, Conn.; Trenton, N.J.; Jersey City, N.J.; Buffalo, N.Y.; and Jackson, Miss.