(CNN) -- President Barack Obama angrily chided lawmakers reluctant to back gun control legislation on Monday, saying the overwhelming support for measures like universal background checks among the American people should force action in Congress.
The president was speaking in Hartford, not far from the site of the massacre in Connecticut that left 20 children and six adults dead at Sandy Hook Elementary School in Newtown.
Obama's calls for tighter gun control laws began in the aftermath of that shooting, though measures he proposed appear to be stalled in Congress.
His message on Monday was crafted as much for lawmakers as it was for the Newtown victims' families, who sat behind him on stage and who will travel to Washington with him on Air Force One to further lobby members of Congress on passing new gun laws.
"Newtown, we want you to know that we're here with you," Obama said. "We will not walk away from the promises we've made. We are as determined as ever to do what must be done. "
The Senate is expected to begin debate as early as this week over proposed firearm legislation, but Democratic sources admit that the gun bill as currently written does not have the 60 votes needed to break a filibuster.
One proposal being considered would expand background checks to gun shows and Internet sales, but would not require checks for any other private transactions, according to multiple sources from both parties who are familiar with the talks. That falls short of the universal background checks favored by Obama.
The powerful National Rifle Association is staunchly opposed to the bill, and a group of 13 Republican senators have already vowed to block the bill, saying the gun legislation will "infringe on the American people's constitutional right to bear arms."
Yet recent polls show an overwhelming majority of Americans favor making a change to the background check system - a fact Obama raised Monday.
"If our democracy's working the way it's supposed to, and 90% agree on something, in the wake of a tragedy, you would think this would not be a heavy lift," Obama said, saying the Republicans who were vowing the filibuster the bill were, in essence, telling Americans that their "opinion doesn't matter."
Some states have gone ahead and passed their own gun control measures, including Connecticut, which expanded its background check system on Thursday among other tough gun laws.
NRA executive vice president Wayne LaPierre blasted the new firearms restrictions, saying the only people who will follow the new regulations are law-abiding gun owners, not criminals.
"I think the problem with what Connecticut did is the criminals, the drug dealers, the people that are going to do horror and terror, they aren't going to cooperate," LaPierre said Thursday on Fox News. "I mean, all you're doing is making the law books bigger for the law-abiding people."
On the federal level, Republican Sen. Tom Coburn of Oklahoma is concerned that the Senate bill could lead to record keeping of gun owners and gun sales. He has been in talks with Sen. Joe Manchin, D-West Virginia, about a compromise, but with nothing promising on the horizon, Democrats have turned to another Republican, Sen. Pat Toomey of Pennsylvania, according to sources familiar with the talks.
Obama's speech Monday night will be the latest in the White House's ongoing push for Congress to pass gun legislation in the wake of a spate of mass shootings last year, including the Newtown massacre and the shooting at the Aurora, Colorado movie theater. Vice President Joe Biden, who spearheaded a task force on coming up with recommendations for Congress, will deliver remarks Tuesday, further putting pressure on Capitol Hill as lawmakers return from, their two-week recess.
CNN's Dana Bash, Jessica Yellin, Ted Barrett, Brianna Keilar, Paul Steinhauser, and Lesa Jansen contributed to this report.