Obama travelled on Saturday to Connecticut's Newtown, a town in mourning after Adam Lanza gunned down 26 people, including 20 first-graders at the Sandy Hook Elementary School before committing suicide last week.
The police said Lanza, 20, used a long rifle and shot the 6-7 year olds multiple times in the carnage that shocked the world and left the America searching for answers. Obama attended an emotional inter-faith memorial service held at the Newtown High School, telling a packed auditorium that the town was not alone in its grief.
He said he offers the love and prayers of the nation but added that the country is failing at its "first task" to keep its children safe. "It's our first job. If we don't get that right, we dont get anything right," he said.
"Can we truly say, as a nation, that we are meeting our obligations? Can we honestly say that we are doing enough to keep our children all of them safe from harm? If we are honest with ourselves, the answer is no," he said.
"We are not doing enough, and we will have to change." Obama said he realises that mere words of condolences are not enough to heal the "wounded hearts" of the parents and friends of those killed in the carnage, which has left the nation "with hard questions."
The shooting is the fourth incident during Obama's term as President and the President said, "we cannot accept events like these" as a routine. "This is the fourth time we have come together to comfort a grieving community torn apart by mass shootings. We cannot tolerate this. These tragedies must end and to end them we we must change," he said.
The memorial service included recitations by inter-faith leaders and prayers for the victims and the first responders.
A young Muslim boy also read verses from the Quran. Obama, sitting in the first row of the auditorium, flanked by city officials and the town's residents, listened to the prayers and sermons intently and somberly.
As the tragedy reopens the debate on the country's gun laws, Obama said, "no single law or set of laws can eliminate evil from the world or prevent every senseless act of violence in our societies. That cannot be an excuse for inaction, surely we can do better than this."
"We cannot accept events like this as routine. Are we really prepared to say we are powerless in the face of such carnage? that the politics are too hard? In the coming weeks I will use whatever power this office holds to engage my fellow citizens," he said, adding "in an effort aimed at preventing more tragedies like this. Because what choice do we have?"
Before participating in the memorial service, Obama met separately with the families of the victims. During the service, the President read out the names of the young children who were killed in the massacre.