Connecticut passed the toughest US law on owning military-style rifles early Thursday, after an impassioned, hours long debate in a state where a gunman massacred 20 small children and six adults in December.
The northeastern state's House of Representatives passed the gun reform bill 105 to 44, the majority Democrats said, clearing the way for its signing into law by Governor Dannel Malloy later in the day.
The assembly's lower house took up the legislation after the state Senate voted 26-to-10 in favor of the law, in the strongest response yet to the December 14 mass killing in Newtown, Connecticut.
"No one is claiming that this bill will prevent all mass killings. But to say that we should do nothing? That is wrong," Democratic State Senator Donald Williams said.
President Barack Obama, campaigning on the issue in Colorado, was set to drive home his message with a visit to Connecticut on Monday.
Under the law, more than 100 makes of rifles -- including the Bushmaster AR-15 used by deranged loner Adam Lanza in Newtown -- are added to an existing, but now vastly expanded ban on assault weapons.
In addition, ammunition clips holding more than 10 rounds must now be registered, while new sales of the large clips are banned.
The law, which raises the minimum age for purchasers from 18 to 21, tightens the procedure for background checks. It also creates the first state registry in the United States of people convicted of gun-related crimes.
Connecticut was set to become the third state, along with New York and Colorado, to vote in new rules following the Newtown killings. More than a dozen others are debating measures.
The shootings at Sandy Hook Elementary School in Newtown were initially seen by many as a watershed moment that could swing public opinion behind national curbs on gun ownership.
However, support has wilted in Congress, with a proposal to ban military style assault weapons and to limit the size of ammunition clips failing to gain traction.
That has left Obama touting expanded background checks on gun purchasers as the centerpiece of his reforms. Even this faces resistance from members of the US Congress heading into re-election races next year in states with strong gun cultures.
Seeking to regain momentum, Obama traveled on Wednesday to Colorado, a western state with a strong hunting tradition and frontier spirit, which nevertheless passed new gun laws after a mass shooting in a cinema killed 12 people last year.
"I don't believe that weapons designed for theaters of war have any place in movie theaters," Obama said, days after expressing frustration that political momentum was fading.
Despite the steady drip of massacres by gunmen in public places, Newtown being just the latest, many Americans remain staunch backers of keeping firearms for sport or self-defense.
Passions over gun ownership -- a right enshrined in the Second Amendment of the US Constitution -- were evident as an unruly crowd opposed to the law burst into the Connecticut state Capitol in Hartford, shouting: "Just say no!"
The focus of anti-gun campaigns has been on the more visible issue of military style rifles. However, nearly all murders in the United States are carried out with pistols.
Nicole Hockley, whose son Dylan died in the Newtown attack, thanked the Connecticut legislature "for listening to us and for approving one of the strongest gun law in the country," the Hartford Courant reported.
"This is going to be something that takes a long time," the newspaper quoted her as saying. "This is just the first step in a multitude of steps. This is progress. Progress is always good."