WITH THE MISSION of stopping the violence that kills an estimated 13 African-American men and boys every 24 hours, Mayor Nutter yesterday welcomed about a dozen mayors and more than 300 other city leaders from around the nation to Philadelphia to work on solutions.

Although the second annual Cities United Convening conference was planned long before this week's riots in Baltimore, that city's troubles were frequently invoked by the attendees at the Philadelphia Marriott Downtown.

"The ability to have these tough conversations and really talk about these issues in concrete ways, I think, is the sum and substance of this work and why this convening is so critically important," Nutter told reporters.

"Given recent incidents across America, including the last 48 hours in Baltimore, this is a very timely conversation," Nutter added.

During his speech opening the two-day conference, Nutter drew applause when he praised Baltimore Mayor Stephanie Rawlings-Blake's handling of the riots and asked the gathered dignitaries to "lift her up."

Kansas City, Mo., Mayor Sly James said his "sympathy and support" was with Baltimore's mayor. He said that mayors across the country have to grapple with the reality that police departments often have "built-in racist tendencies" and don't always reflect the racial composition of the communities they serve.

"That creates friction in and of itself, and it's been there for quite some time," he said.

"The goal has to be bringing people together in a way that alleviates that distrust, allows everybody to understand that the police have a job, we in the community have a responsibility . . . and to find a way to work together."

Cities United Convening - whose membership includes 76 mayors - was launched in 2011 by Nutter; New Orleans Mayor Mitch Landrieu; and William C. Bell, president of the Casey Family Programs.

In addition to Nutter and James, attending this week's conference are the mayors of Camden; Birmingham, Ala.; Gary, Ind.; Madison, Wis.; Minneapolis; Newton, Mass.; Patterson, La.; Riviera Beach, Fla., and Washington, D.C.

On Twitter: @MensahDean