US President Barack Obama has directed a Cabinet group to give him recommendations by next month on ways to tighten the regulation of guns in the wake of the Connecticut massacre of 20 schoolchildren last Friday.
Mr Obama held a White House news conference to announce that Vice President Joe Biden will lead an effort to crack down on gun violence.
Mr Obama said he believed Americans would support the reinstatement of a ban on the sale of military-style assault weapons.
He also wants a ban on the sale of high-capacity ammunition clips, and a law requiring background checks on buyers before all gun purchases.
This would close a loophole that allows sales at open-air gun shows without such background checks.
Saying gun control cannot be the only solution to the problem, Mr Obama expressed support for making it easier for Americans to get access to mental health care - "at least as easy as access to a gun".
Under pressure from fellow Democrats to act, Mr Obama insisted the guns issue would not be ignored this time.
Previous appeals for more gun regulation have died even as mass shootings have continued.
With Mr Biden at his side, Mr Obama said the group would give him proposals that he could outline in his State of the Union speech in late January.
Cabinet members involved include Attorney General Eric Holder, Homeland Security Secretary Janet Napolitano, Health and Human Services Secretary Kathleen Sebelius and Education Secretary Arne Duncan.
"This is not some Washington commission. This is not something where folks are going to be studying the issue for six months and publishing a report that gets read and then pushed aside.
“This is a team that has a very specific task to pull together real reforms right now," Mr Obama said.
The Newtown, Connecticut, shootings of so many schoolchildren by a 20-year-old man have shocked Americans in ways that previous mass shootings have not.
The gunman's mother and six adults at the school were also killed before the gunman shot himself.
Some previously adamant opponents of increased gun control have expressed a willingness to consider more regulation.
Even the powerful National Rifle Association, the lobby group that has sought time and again to stymie gun legislation, said this week that it would be prepared to offer meaningful contributions to ensure there is no repeat of Newtown.
Mr Obama himself has done little to rein in America's gun culture in his four years in office.
His administration has to a certain extent expanded gun rights by permitting the carrying of firearms in national parks.
Asked why he has been a no-show on the subject until now, Mr Obama defended himself, saying he has been dealing with the worst economic crisis since the Great Depression and wars in Iraq and Afghanistan.
"I don't think I've been on vacation," he said. The Newtown massacre, he said, "should be a wake-up call for all of us".
Whatever steps Mr Obama's task force comes up with are likely to face some criticism because many Republicans see the US Constitution's Second Amendment right to bear arms as sacrosanct.
"What we're looking for here is a thoughtful approach that says we can preserve our Second Amendment, we can make sure that responsible gun owners are able to carry out their activities, but that we're gonna actually be serious about the safety side of this," Mr Obama said.
Mr Obama has tapped Mr Biden to lead other high-profile initiatives, including efforts on a deficit-reduction compromise with congressional Republicans in 2011.
US Representative Ron Barber, who was wounded in a 2011 Arizona shooting that targeted his predecessor, Gabrielle Giffords, welcomed the effort and echoed other Democratic lawmakers' calls to ban military-grade guns.
"We cannot go on blithely believing that we can solve this problem in other ways. We have to look at the weaponry used and we have to look at the people who use it and we have to do something about both," Mr Barber said at a news conference earlier at the Capitol.
Friday's massacre was the fourth shooting rampage to claim multiple lives in the United States this year.