Thousands of people, many holding signs with the names of gun violence victims and messages such as "Ban Assault Weapons Now," joined a rally for gun control on Saturday, marching from the Capitol to the Washington Monument.

Leading the crowd were marchers with "We Are Sandy Hook" signs, paying tribute to victims of the December elementary school shooting in Newtown, Connecticut. Washington Mayor Vincent Gray and other city officials marched alongside them. The crowd stretched for at least two blocks along Constitution Avenue.

Participants held signs reading "Gun Control Now" "What Would Jesus Pack?" among other messages. Other signs were simple and white, with the names of victims of gun violence.

About 100 residents from Newtown, where a gunman killed 20 students and six educators, travelled to Washington together, organizers said.

A shooting rampage at Sandy Hook Elementary School in Newtown, Conn., on Dec. 14, 2012 killed 26 people. (Shannon Hicks/Associated Press)

Actor Kathleen Turner spoke at the event urging people to take action and write letters to their local politicians so changes can be made in Washington.

"It's wonderful that we're all here today. And you listen to people with good common sense. Action that can and must be taken. But there's obviously more that needs to be done...."

Participant Kara Baekey from nearby Norwalk, Connecticut., said that when she heard about the Newtown shooting, she immediately thought of her two young children. Baekey decided she must take action, and that's why she travelled to Washington for the march.

'It just can't happen again'

"I wanted to make sure this never happens at my kids' school or any other school," Baekey said. "It just can't happen again."

Once the crowd arrived at the monument, speakers called for a ban on military-style assault weapons and high-capacity ammunition magazines and for universal background checks on gun sales.

Education Secretary Arne Duncan told the crowd it's not about taking away gun rights guaranteed by the U.S. Constitution's Second Amendment, but about gun safety and saving lives. He said he and President Barack Obama would do everything they could to enact gun control policies.

"This is about trying to create a climate in which our children can grow up free of fear," Duncan said. "This march is a starting point; it is not an ending point ... We must act, we must act, we must act."

Eleanor Holmes Norton, Washington, D.C.'s non-voting representative in Congress, said the gun lobby can be stopped, and the crowd chanted back, "Yes, we can."

"We are all culpable if we do nothing now," Norton said.

Molly Smith, the artistic director of Washington's Arena Stage, and her partner organized the march.

'We are all culpable if we do nothing now.'—Elanor Holmes Norton, Washington D.C.'s representative in Congress

Organizers said that in addition to the 100 people from Newtown, buses of participants travelled from New Jersey, New York and Philadelphia. Others flew in from Seattle, San Francisco and Alaska, they said.

While she's never organized a political march before, Smith said she was compelled to press for a change in the law. The march organizers support Obama's call for gun control measures. They also want lawmakers to require gun safety training for all buyers of firearms.

"With the drum roll, the consistency of the mass murders and the shock of it, it is always something that is moving and devastating to me. And then, it's as if I move on," Smith said. "And in this moment, I can't move on. I can't move on.

"I think it's because it was children, babies," she said. "I was horrified by it."

After the Connecticut shootings, Smith began organizing on Facebook. The group One Million Moms for Gun Control, the Washington National Cathedral and two other churches eventually signed on to co-sponsor the march. Organizers have raised more than $50,000 online to pay for equipment and fees to stage the rally, Smith said.

Lawmakers from Washington, D.C., and Maryland rallied the crowd, 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 U.S. history.

Goddard said he was shot four times at Virginia Tech and is motivated to keep fighting for gun control because what happened to him keeps happening -- and nothing's been done to stop it.

"We are Americans," he said, drawing big cheers. "We have overcome difficulties when we realize we are better than this."

Smith said she supports a comprehensive look at mental health and violence in video games and films. But she said the mass killings at Virginia Tech and Aurora, Colorado, and Newtown, Connecticut., all began with guns.

"The issue is guns. The Second Amendment gives us the right to own guns, but it's not the right to own any gun," she said. "These are assault weapons, made for killing people."