The US is obliged to change in the wake of the school shooting that killed 20 students and six teachers last Friday, the US ambassador has said.
“Now is the time,” said Gina Abercrombie-Winstanley, when asked if it was time to change US gun laws.
“The events at Newtown, Connecticut, exceptional in their sheer abhorrence, mark a galvanising moment,” she added.
The deaths at Sandy Hook Elementary School in Newtown have kindled debate about the country’s gun rights.
Investigators believe Adam Lanza, 20, used a Bushmaster .223 assault rifle and two handguns to kill his victims, including 20 children no older than seven.
All the guns were obtained legally by his mother, whom he also killed.
US President Barack Obama told a vigil in the town on Sunday that he would use whatever po-wer his office held to prevent similar tragedies.
He did not specify changes to gun laws, but his comments have lifted the spirits of supporters of tighter firearm restrictions.
“President Obama said that our first job is caring for our children – that is how society is judged,” Ms Abercrombie-Winstanley said.
“The kind of violence that occurred in Newtown happens, unfortunately, all too often in the US.”
She pointed out that the US President supported reinstating an assault weapons ban that expired in 2004.
Asked if this went far enough, she said: “This is a complex problem that requires a complex solution.
“No single piece of legislation, no single action will eliminate it. However, the President is committed to addressing the difficult politics of this issue.”
The US Government has taken steps to improve background checks, she added.
“But as the President clearly stated, while we are not yet doing enough, we are certainly not powerless to act.
“He affirmed that we can change, even in the face of obstacles.”
The second amendment to the US Constitution grants American citizens the right to bear arms.
Politicians have long been wary of advocating tighter restrictions on this right for fear of upsetting the powerful gun lobby.
But there were signs of changes on Capitol Hill in recent days, with Democratic Senators and known gun rights advocates Joe Manchin and Mark Warner both speaking in favour of reform.
The Newtown massacre was the second mass shooting in the US this year. A gunman killed 12 people during a screening of Batman film The Dark Knight Rises in Aurora, Colorado, in July.