WASHINGTON: Just days before the Senate begins debating new gun control measures proposed by President Barack Obama, 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 in the U.S. capital.

Leading the crowd Sunday 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" and "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, traveled to Washington together, organizers said.

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 traveled to Washington for the march.

"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 expressed support for Obama's proposals 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."

But in the Senate, some of Obama's fellow Democrats may frustrate his efforts to enact the most sweeping gun control measures in decades. These Democrats from largely rural states with strong gun cultures view Obama's proposals warily and have not committed to supporting them.

"There's a core group of Democratic senators, most but not all from the West, who represent states with a higher-than-average rate of gun ownership but an equally strong desire to feel their kids are safe," said Mark Glaze, director of Mayors Against Illegal Guns. "They're having hard but good conversations with people back home to identify the middle-ground solutions that respect the Second Amendment but make it harder for dangerous people to get their hands on guns."

All eyes are on these dozen or so Democrats, some of whom face re-election in 2014. That includes Sens. Max Baucus of Montana, Mark Begich of Alaska and Mark Pryor of Arkansas.

The Senate Judiciary Committee begins hearings Wednesday.

Interest groups, lobbyists, lawmakers, crime victims and others with a stake in the outcome will be watching these senators closely for signals about what measures they might support.

Leading the charge against those ideas is the National Rifle Association. The gun rights lobbying group wields enormous power to rally public sentiment and is a particular threat to Democrats in pro-gun states who face re-election.

At Saturday's rally, 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. Organizers said that buses of participants traveled 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 gun laws.

"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.

Colin Goddard, who survived after being shot four times in the 2007 Virginia Tech massacre that left 32 dead, the largest mass shooting in U.S. history, said he 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."

But even before Obama announced his gun proposals earlier this month, Senate Majority Leader Harry Reid told a Nevada television station that an assault weapons ban would have a hard time getting through Congress. That comment irked Democratic Sen. Dianne Feinstein of California, author of such a ban.

"Clearly it wasn't helpful," she said this past week in reintroducing her measure. But Feinstein's original assault weapons ban was a stern political lesson for Reid and other Democrats. Its passage as part of President Bill Clinton's crime bill in 1994 was blamed for Democratic election losses that year after the NRA campaigned against lawmakers who supported the legislation. When the assault weapons ban came up for renewal in 2004, Congress, under pressure from the NRA, refused to extend it.

Reid has pledged action on gun measures. "This is an issue we're not going to run from," he said. But he's under pressure from all sides. The NRA, which mostly backs Republicans, endorsed Reid in previous elections, but stayed neutral in his most recent race, in 2010.

"I'm concerned just because Harry Reid has a mixed record on these things and we want him to be a champion," said Josh Horwitz, executive director of the Coalition to Stop Gun Violence.

On the other side, the NRA, known for rewarding friends and punishing enemies, promises it will be closely watching Reid, too.

"He's going to be torn and a lot of people are going to be torn, particularly Democrats, but I think as the debate goes on he'll do more good than bad from our perspective," said David Keene, NRA president. "All this stuff has been debated before and once you get into a debate and a discussion and say will this do anything to protect children, to prevent another Newtown, I think the answer is going to come out 'no.'"

The NRA generally opposes legislation mandating universal background checks and disputes gun control groups' claims that 40 percent of purchases happen without such checks. NRA officials question whether background checks could be done effectively in a way that makes a difference and doesn't disrupt legitimate sales.

The NRA's executive vice president, Wayne LaPierre, is to testify Wednesday before the Senate Judiciary Committee.