By Ian Simpson

WASHINGTON (Reuters) - Thousands of marchers rallied in Washington in favor of gun control on Saturday, including residents of Newtown, Connecticut, where a mass elementary school shooting reignited the U.S. gun violence debate.

Speakers - including Education Secretary Arne Duncan, lawmakers and actors - urged the protesters carrying such signs as "What Would Jesus Pack?" to lobby Congress and state legislators to back gun control measures.

Duncan, who said one student had died from guns every two weeks while he was chief executive of Chicago's public schools, denied that gun control was about limiting firearm rights guaranteed by the U.S. Constitution. Murders in that city last year rose to the highest level since 2008, according to police.

"This is about gun responsibility. This is about gun safety. This is about fewer dead Americans, fewer dead children, fewer children living in fear," Duncan said.

Organizers backed President Barack Obama's call for a ban on military-style assault weapons and high-capacity ammunition magazines and background checks for all gun sales. They also urged safety training for all buyers of firearms.

Marchers stretched for several blocks along Constitution Avenue as they approached the rally site in the shadow of the Washington Monument.

Participants included politicians from Maryland and the District of Columbia, including Washington Mayor Vincent Gray, as well as actress Kathleen Turner and Marian Wright Edelman, founder of the Children's Defense Fund.

90-MINUTE RALLY

The protest came a week after gun rights supporters held rallies across the United States to oppose firearms control.

The 90-minute rally was organized by Molly Smith, artistic director of Washington's Arena Stage, and her partner, and co-sponsored by One Million Moms for Gun Control, an advocacy group.

One Million Moms organized similar events on Saturday in about a dozen cities, including San Francisco and Austin, Texas. Continued...