Sen. Joe Manchin of West Virginia, an avid hunter and lifelong member of the National Rifle Association, on Monday became the latest lawmaker - and the first prominent gun rights supporter - to call for action.
"Anybody that's a proud gun owner, a proud member of the NRA, they're also proud parents, they're proud grandparents. They understand this has changed where we go from here," Manchin told MSNBC's "Morning Joe."
Several other Democrats and Independent Sen. Joe Lieberman say high-powered, military-style weapons and large ammunition clips are too readily available. Gun-control legislation is expected to be introduced in Congress next year.
Gun control was a hot topic in the early 1990s, when Congress enacted a 10-year ban on assault weapons. But since that ban expired in 2004, few Americans have wanted stricter laws and politicians say they don't want to become targets of a powerful gun-rights lobby.
Gun-rights advocates said that might all change after the latest shooting that killed 20 children aged 6 or 7. Police say the gunman, Adam Lanza, was carrying an arsenal of ammunition and used a high-powered rifle similar to the military's M-16.
At a Sunday night service in Newtown, Conn., the site of Friday's massacre, President Barack Obama did not specifically address gun control. But he vowed, "In the coming weeks I'll use whatever power this office holds to engage my fellow citizens, from law enforcement to mental health professionals to parents and educators in an effort aimed at preventing more tragedies like this."
He added: "Are we really prepared to say that we're powerless in the face of such carnage, that the politics are too hard? Are we prepared to say that such violence visited on our children year after year after year is somehow the price of our freedom?"
Sen. Chuck Schumer, D-N.Y., said the nation "could be at a tipping point ... a tipping point where we might actually get something done" on gun control. He and other Democrats, as well as Lieberman, said they want to ban the sale of new assault weapons and make it harder for mentally ill individuals to obtain weapons. Lieberman said a new commission should be created to look at gun laws and the mental health system, as well as violence in movies and video games.
"This is bigger than just about guns," he said Monday. "It's about how we treat people with mental illness, how we intervene, how we get them the care they need, how we protect our schools. It's just so sad."
Manchin, a self-described "proud outdoorsman and hunter," said, "I don't know anyone in the sporting or hunting arena that goes out with an assault rifle, I don't know anybody who needs 30 rounds in a clip to go hunting."
Sen. Dianne Feinstein, D-Calif., said she will introduce legislation next year to ban new assault weapons, as well as big clips, drums and strips of more than 10 bullets.
"It can be done," Feinstein told NBC's "Meet the Press" of reinstating the ban despite deep opposition by the powerful National Rifle Association and similar groups.
New York Mayor Michael Bloomberg said Obama could use executive powers to enforce existing gun laws, as well as throw his weight behind legislation like Feinstein's.
"It's time for the president, I think, to stand up and lead and tell this country what we should do - not go to Congress and say, 'What do you guys want to do?'" Bloomberg said."
Gun-rights activists had remained largely quiet on the issue since Friday's shooting, all but one declining to appear on the Sunday talk shows.
David Gregory, the host of "Meet the Press," said NBC invited all 31 "pro-gun" senators to appear on Sunday's show, and all 31 declined. All eight Republicans on the Senate Judiciary Committee were unavailable or unwilling to appear on CBS' "Face the Nation," host Bob Schieffer said.
Rep. Louie Gohmert, R-Texas, was the sole representative of gun rights' activists on the various Sunday talk shows. In an interview on "Fox News Sunday," Gohmert defended the sale of assault weapons and said that the principal at Sandy Hook Elementary School, who authorities say died trying to overtake the shooter, should herself have been armed.
"I wish to God she had had an M-4 in her office, locked up so when she heard gunfire, she pulls it out and she didn't have to lunge heroically with nothing in her hands. But she takes him (the shooter) out, takes his head off before he can kill those precious kids," Gohmert said.
Gohmert also argued that violence is lower in cities with lax gun laws, and higher in cities with stricter laws.
"The facts are that every time guns have been allowed - conceal-carry (gun laws) have been allowed - the crime rate has gone down," Gohmert said.
Gun-control advocates say that isn't true. A study by the California-based Law Center to Prevent Gun Violence determined that 7 of the 10 states with the strongest gun laws - including Connecticut, Massachusetts and California - are also among the 10 states with the lowest gun death rates.
"If you look at the states with the strongest gun laws in the country, they have some of the lowest gun death rates, and some of the states with the weakest gun laws have some of the highest gun death rates," said Brian Malte of the Brady Campaign to Prevent Gun Violence.
Associated Press writers Jim Kuhnhenn and Josh Lederman contributed to this report.