Thousands of people, many holding signs with the names of gun violence victims and messages such as "Ban Assault Weapons Now", have joined a rally for gun control in the US.
Participants were led from the Capitol to the Washington Monument by the city's mayor Vincent Gray and other officials, and the crowd stretched for about two blocks along Constitution Avenue. Police blocked off half the road.
Participants held signs reading " Gun Control Now" and "Stop NRA", referring to the National Rifle Association, and influential gun rights lobbying groups, among other messages. Other signs were simple and white, with the names of victims of gun violence.
About 100 residents were expected from Newtown, Connecticut, where a gunman killed 20 children and six adults at the Sandy Hook Elementary School in December. The rally was organised in response to that shooting.
Once the crowd arrived at the monument, speakers called for a ban on military-style assault weapons and high-capacity ammunition magazines.
Education Secretary Arne Duncan told the crowd the issue is not about taking away constitutional rights to keep and bear arms, but about gun safety and saving lives. He said he and President Barack Obama would do everything they could to enact gun control policies.
"We must act, we must act, we must act," he said.
Norton said the nation did not act after previous mass killings, but she said "we the people" will not give up this time. "We are all culpable if we do nothing now," she said
Actress Kathleen Turner was also expected to appear, along with Marian Wright Edelman of the Children's Defence Fund and Colin Goddard, a survivor from the 2007 Virginia Tech massacre that left 32 dead, the largest mass shooting in US history.