US President Barack Obama is proposing a new assault weapons ban and mandatory background checks for all gun buyers in a bid to channel national outrage over the Connecticut school massacre into the biggest gun-control push in generations.
The National Rifle Association immediately dismissed Obama's proposals, saying they amounted to an attack on firearms and would affect only law-abiding gun owners.
"We look forward to working with Congress on a bi-partisan basis to find real solutions to protecting America's most valuable asset - our children," the powerful gun lobby group said.
"Attacking firearms and ignoring children is not a solution to the crisis we face as a nation. Only honest, law-abiding gun owners will be affected and our children will remain vulnerable to the inevitability of more tragedy," the NRA said.
In rolling out the wide-ranging plan for executive and legislative action against gun violence, Obama has set up a fierce clash with the NRA and its supporters in Congress.
Obama presented his agenda at a White House event in front of an audience that included children from around the country, a poignant reminder of the 20 children who were killed along with six adults by a lone gunman on December 14 at Sandy Hook Elementary School in Newtown.
"While reducing gun violence is a complicated challenge, protecting our children from harm shouldn't be a divisive one," Obama said.
Until now, Obama had done little to rein in America's weapons culture during his first four years in office.
But just days before his second inauguration, he appears determined to champion gun control in his next term with a concerted drive for tighter laws and other steps aimed at preventing further tragedies like the one at Newtown.
The proposals stem from a month-long review led by Vice President Joe Biden, who, on orders from Obama, met advocates from both sides of the gun debate, including representatives from the weapons and entertainment industries.
Obama's plan calls on Congress to renew the prohibition on assault weapons sales that expired in 2004, a requirement for criminal background checks on all gun purchases, including closing a loophole for gun show sales, and a new federal gun trafficking law - long sought by big-city mayors to keep out-of-state guns off their streets.
He also announced 23 steps he intended to take immediately without congressional approval.
These include improvements in the existing system for background checks, lifting the ban on federal research into gun violence, putting more counsellors and "resource officers" in schools, and improved access to mental health services.
The most politically contentious piece of the package is Obama's call for a renewed ban on military-style assault weapons, a move that Republicans who control the House of Representatives are expected to oppose.
The Newtown gunman, 20-year-old Adam Lanza, used a Bushmaster AR-15 assault rifle to shoot his victims, many of them six- and seven-year-olds, before killing himself.
Underscoring the tough political fight ahead, the NRA launched a scathing advertising campaign against Obama's gun control effort and deployed its representatives in force on Capitol Hill.
The NRA, which says it has about four million members, took aim at Obama in a stinging TV and internet ad, accusing him of being "just another elitist hypocrite" for accepting Secret Service protection for his two daughters but turning down the lobby group's proposal to put armed guards in all schools.
Obama's plan appears to tread cautiously on the question of whether violent movies and video games contribute to the gun violence, which would open up issues of freedom of expression.
A senior administration official said, however, that Obama would be asking for US$10 million for the federal Centers for Disease Control and Prevention to study the root causes of gun violence, including any relationship to video games and media images.
Much of the fight over gun control in the US centres on the second amendment of the US Constitution, which reads:
"A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed."