Newark's Cory Booker, the Democratic nominee in New Jersey's Senate race was among the attendees, as were Atlanta's Kasim Reed, Philadelphia's Michael Nutter and Washington's Vincent Gray. The meeting comes just a day before the 50th anniversary of Martin Luther King Jr.'s "I Have a Dream" speech and as Obama prepares to deliver his own speech Wednesday to mark the anniversary.
The president also said he would "continue doing everything in his power to combat gun violence through executive action and to press Congress to pass common-sense reforms like expanding the background check system and cracking down on gun trafficking."