WASHINGTON: The United States' most powerful pro-gun lobbying group demanded on Friday that armed police be deployed to every school in the country following a mass shooting that left 20 young children dead.

The National Rifle Association, which defends what it sees as US citizens' constitutional right to bear arms, had been under pressure to respond in the wake of last week's massacre.

But NRA leaders, in a combative and determined public appearance, ceded no ground to those calling for tougher gun laws.

“The only thing that stops a bad guy with a gun is a good guy with a gun,” declared NRA vice-president Wayne LaPierre, in the group's first reaction since the shooting at the Sandy Hook Elementary School in Newtown, Connecticut.

“I call on Congress today to act immediately to appropriate whatever is necessary to put armed police officers in every single school in this nation,”he said, in a lengthy statement. He took no questions from reporters.

LaPierre said the NRA was ready to help train security teams for schools and work with teachers and parents to improve security measures, and accused the media and the political class of demonizing gun owners.

On Friday, a troubled 20-year-old man burst into the Sandy Hook school and gunned down 20 six- and seven-year-old children and six staff members trying to protect them, before taking his own life.

The massacre was only the latest in a series of mass shootings in the United States this year, and prompted President Barack Obama to throw his weight behind plans to revive a ban on assault weapons.

America has suffered an epidemic of gun violence over the last three decades including 62 mass shooting incidents since 1982. The vast majority of weapons used have been semi-automatic weapons obtained legally by the killers.

There were an estimated 310 million non-military firearms in the United States in 2009, roughly one per citizen, and people in America are 20 times more likely to be killed by a gun than someone in another developed country.

But LaPierre insisted gun ownership was not the problem.

“You know, five years ago after the Virginia Tech tragedy when I said we should put armed security in every school, the media called me crazy,” he said, referring to a 2007 campus shooting that left 32 people dead.

“But what if, what if when Adam Lanza started shooting his way into Sandy Hook Elementary School last Friday he'd been confronted by qualified armed security?” he demanded.

“Will you at least admit it's possible that 26 little kids, that 26 innocent lives might have been spared that day? Is it so abhorrent to you that you'd rather continue to risk the alternative?”

The statement did not impress Chris Murphy, the congressman who represents the district that includes the school.

“Walking out of another funeral and was handed the NRA transcript. The most revolting, tone deaf statement I've ever seen,” he said, on Twitter.

And the statement immediately drew criticism from supporters of tougher gun control, who are pushing to ban semi-automatic assault weapons like the .223 Bushmaster rifle that Lanza used in Friday's shooting.

“The NRA leadership's drive to fill our schools with more deadly guns and ammo is wildly out of touch with responsible gun owners and the American public,” New Jersey Senator Frank Lautenberg said.

The protesters that attempted to drown out LaPierre's statement were more blunt. One bore a banner reading “NRA kills our kids” the other “NRA has blood on its hands.” They were led away by security.

But LaPierre ploughed on, warning that more killers are actively plotting to attack schools.

And he slammed and attacked media conglomerates, denouncing violent video games, music videos that celebrate crime and Hollywood movies that glamorize violence.

“Isn't fantasising about killing people as a way to get your kicks really the filthiest form of pornography?” he demanded.

“Too many in the national media, their corporate owners and their stockholders act as silent enablers, if not complicit co-conspirators. Rather than face their own moral failings, the media demonise gun owners.”