The gunman who killed 26 people, including 20 children, in a shooting spree in a US elementary school fired 155 bullets in less than five minutes. Court papers released reveal he also had several additional firearms not used in the attack.
President Obama has said there will be "shame" on himself and the American people if pledges to bring in tougher gun safety laws after the Newtown school massacre go unfulfilled.
More than 3,000 gun deaths have occurred in the US since Adam Lanza shot dead 26 children and staff at Sandy Hook Elementary School in Connecticut in December.
More shocking details of the speed of the attack and the arsenal of weapons Lanza owned have been released today.
But, as ITV News Correspondent Geraint Vincent reports from Washington, DC, Mr Obama still faces great difficulty in translating anger at the massacre into legislation aimed at curbing the public's right to bear the most powerful of arms.
Newtown killer Adam Lanza's choice of assault weapons from his store of guns to carry out the December school massacre underlines why tighter controls are needed, Connecticut Governor Dannel Malloy has said.
"We now know that he left the lower capacity magazines at home," Malloy said in a statement after the previously sealed searches of Lanza's car and home were made public.
"This is exactly why we need to ban high capacity magazines and why we need to tighten our assault weapons ban."
The release of the new details surrounding the Newtown massacre and Adam Lanza's vast arsenal of weapons has only inflamed emotional wounds for some in the Connecticut town.
We struggle every day to stay on the path of recovery and every bit of information that becomes part of the public discourse holds a potential hurt for a family who has already suffered immeasurable harm.
I appreciate that full and accurate information may help us, as a society, learn how to predict and prevent such horrors from happening in the future. That gain, however speculative, must be balanced against the hurt experienced by those in the eye of the storm.
Documents released today about the Sandy Hook shootings reveal the items seized by police from the home of gunman Adam Lanza.
Among the items were a card containing a cheque from his mother to buy a firearm, an article from The New York Times about a school shooting at Northern Illinois University and three photographs of what appeared to be a dead person covered with plastic and blood, NBC reports.