NEWTOWN, Connecticut: The debate many gun control advocates have been hoping for in America erupted on the Sunday morning political TV programs.
The Democratic senator Dianne Feinstein told Meet the Press she would introduce a comprehensive gun reform bill on the first day of Congress.
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Lanza used military style rifle
James Holmes, Martin Bryant and Adam Lanza all used a similar style of semi-automatic rifle similar to gun down their victims.
''I'm going to introduce in the Senate - and the same bill will be introduced in the House - a bill to ban assault weapons,'' she said.
''It will ban the sale, the transfer, the importation, and the possession - not retroactively but prospectively'' of assault weapons, she said.
Crucially, the bill would also ban the sale, transfer, importation and possession of clips of more than 10 bullets.
''The purpose of this bill is to get … weapons of war off the streets of our cities,'' she said.
It is not clear such a bill would pass the Senate, where Democrats hold a slim majority, let alone the Republican-dominated House of Representatives.
Senator Feinstein was the author of a previous law that banned the ownership of assault rifles that was in place between 1994 and 2004, when Congress allowed it to expire. That bill was blamed for 34 Democrat incumbents losing their seats.
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In his memoir, the former president Bill Clinton said the National Rifle Association's campaign against the law led to Newt Gingrich becoming Speaker, and ended four decades of Democrat dominance of the House.
One of the most outspoken opponents of the gun lobby, the mayor of New York, Michael Bloomberg, also appeared on Meet the Press, arguing that the NRA's influence was overrated and saying gun control should be Mr Obama's top priority.
The Democrat Governor of Connecticut, Dan Malloy, also called for tighter controls on semi-automatic weapons. ''These are assault weapons - you don't hunt deer with these things,'' he told CNN's State of the Union. ''One can only hope we'll find a way to limit these weapons that really only have one purpose.''
On Fox News Sunday the retiring independent senator from Connecticut Joe Lieberman said he supported the restoration of the ban on assault weapons, and called for a national commission on mass violence, considering not just gun law but also the depiction of violence in the media.
''Americans need to make sure that the heartbreak and anger that we feel now is not dissipated over time or lost in legislative gridlock'', he said.
The Senate Democratic Whip Dick Durbin of Illinois voiced his support for such a commission.
''This conversation has been dominated in Washington by - you know and I know - gun lobbies that have an agenda.
''We need people, just ordinary Americans, to come together and speak out and to sit down and calmly reflect on how far we go.''
Also appearing on Fox News was the Texan Republican congressman Louie Gohmert, who had a different view.
''I wish to God she [slain school principal Dawn Hochsprung] had had an M4 [assault rifle] in her office, locked up, so when she heard gunfire, she pulls it out … and takes him out and takes his head off before he can kill those precious kids,'' he said.
He said it was important citizens were armed so they could resist government tyranny.
''Once you start drawing the line, where do you stop? That's why it is important to not just look at this emotionally.''
NBC said it had invited all pro-gun senators to appear on Meet the Press but none were willing.
In line with its standard practice after mass shootings the NRA has declined to comment, but some of its prominent supporters have already spoken out.
The former governor and Republican candidate Mike Huckabee blamed the violence on the removal of God from schools, while the commentator Ann Coulter tweeted that so-called ''concealed carry'' reduced the murder rate.
The debate had raged on talkback radio and social media since the shootings.
One caller to a Connecticut radio station, who said he was a former police officer, said teachers should be armed and trained to use weapons.
Connecticut officials said Newtown region schools would be protected by armed police this week in an effort to allay fears of parents and students.