Outside the White House on Friday, the crowd held candles and chanted, "Today is the day." Some dabbed tears. People carried signs reading, "Too many guns" and "Disarm".

Anna Oman of Silver Spring, Maryland, was in the crowd with her 5-year-old son, Hugo.

Supporters of gun control legislation hold candles during a rally in front of the White House in Washington, after a gunman killed 27 people, including 20 children, in Newtown, Connecticut Dec 14, 2012. [Photo/Agencies]

"I felt today like I did on September 11," she said. "I had to do something."

NRA spokesman Andrew Arulanandam said in an email: "Until the facts are thoroughly known, NRA will not have any comment."

The NRA's strength could be tested anew after its largely unsuccessful efforts in the 2012 election. The organization pushed strongly for Obama's defeat, and most of its favored candidates for the US Senate lost.

Any national gun legislation would face its most difficult obstacle in the House, whose Republican leaders have strong ties to the NRA.

BOEHNER'S 'A' RATING

House Speaker John Boehner has received an "A" rating in the past from the NRA, the largest lobbying group for gun owners and makers. Boehner released a statement mourning the deaths in Connecticut, but the Republican leader would have no comment on possible gun control legislation, a spokesman said.

Another lawmaker with an "A" rating from the NRA, Virginia Republican Representative Bob Goodlatte, will have jurisdiction over gun bills when he starts next month as the new chairman of the House Judiciary Committee. A spokeswoman did not respond to a request for comment on Friday.

Mark Glaze, director of Bloomberg's group, Mayors Against Illegal Guns, said it would take presidential involvement for the issue to gain momentum.

"After Tucson, after Aurora, and now after Newtown, we've been told it's time for a moment of silence. And that moment of silence stretches into months. The president could actually make a difference, and it's time for him to try," Glaze said.

On social media, some people responded to the Connecticut shooting by trying to coin new terms to replace "gun control," such as "massacre prevention".

There is no shortage of ideas among gun control advocates.

They could push to require background checks for all gun purchases; checks are now required only at licensed commercial dealers but not among private sellers. They could also push for a federal law on gun trafficking, for tougher sentences for illegal purchases or for more resources for the US Bureau of Alcohol, Tobacco, Firearms and Explosives.

US Attorney General Eric Holder was in Connecticut this month to talk about guns - but only about gun violence among gangs, not gun control generally.

On Wednesday, a day after a shooting at an Oregon shopping mall, Holder told reporters that the Obama administration was in discussions about proposals but he made no commitments.

"There are a number of proposals that we're in the process of considering, and I expect that you will be hearing from the administration," Holder said.