"We've endured too many of these tragedies in the past few years," Obama said during a televised appearance in the White Housebriefing room just hours after one of the worst mass shootings in U.S. history.
Pausing to collect himself as he expressed "overwhelming grief" as a parent, Obama deplored the "heinous" attack by a heavily armed gunman at a school in Newtown, Connecticut that killed 26 people, including 20 children. The shooter is also dead, police said.
Obama, who has responded to previous shooting massacres by citing the need for a national conversation about gun violence, again stopped short of calling for tougher gun-control laws, considered a politically risky in a country known for its flourishing gun culture.
But, little more than a month after his decisive re-election to a second term, he suggested that in the aftermath of Friday's tragedy he might be ready to take a more assertive approach.
"As a country, we have been through this too many times," Obama said, ticking off a list of recent shootings.
"And we're going to have to come together and take meaningful action to prevent more tragedies like this, regardless of the politics," he said, in an apparent reference to the influence of the National Rifle Association, a powerful pro-gun lobby, over members of Congress.
Obama avoided making direct calls for gun control during his bitterly fought campaign for a second term, which he secured in a November 6 election.
PAUSE IN PARTISAN BICKERING
But partisan bickering in Washington, divided as much as ever before by a battle over a looming "fiscal cliff" of tax hikes and spending cuts, was put on hold on Friday amid mourning for the dead at Sandy Hook Elementary School.
Obama ordered flags at federal buildings to be lowered to half-mast and he canceled an official trip to Maine scheduled for Wednesday. There was no immediate word from the White House on when the president might visit Connecticut to console grieving families.
"Our hearts are broken today, for the parents, and grandparents, sisters and brothers of these little children and for the families of the adults who were lost," Obama said, his voice cracking with emotion.
"Our hearts are broken for the parents of the survivors as well, for as blessed as they are to have their children home tonight, they know that their children's innocence has been torn away from them too early and there are no words that will ease their pain," he said.
Obama, who has two young daughters, looked grim when he entered the briefing room, and he paused and blinked hard after mentioning the ages of the dead children - from 5 to 10 years old.
"I know there's not a parent in America who doesn't feel the same overwhelming grief that I do," he said.
Obama raised a finger and dabbed at the corner of his eye on several occasions. While speaking, he set his jaw several times. At the end of his statement, there was a tear visible below his left eye and that side of his face was slightly wet.
Obama has issued public statements before in the aftermath of shooting massacres.
Following the killing of six people at a Sikh temple in Wisconsin in early August, he said such incidents should prompt soul-searching by all Americans.
But when asked then whether he would push for further gun-control measures in the wake of the shootings, Obama said only that he wanted to bring together leaders at all levels of American society to examine ways to curb gun violence.
The president has said he supports the reinstatement of a ban on assault weapons sales, but has done little in his first term to advance that.
Asked about gun control on Friday, White House spokesman Jay Carney told reporters that the immediate aftermath of the Connecticut shooting was not the right time for policy debates.
Outside the White House gates, several dozen people held a candlelight vigil for the victims, holding anti-gun posters with slogans like "no more lives shattered by gun violence."
(Additional reporting by Jeff Mason and Steve Holland; Editing by Peter Cooney and David Brunnstrom)