NEWTOWN, Conn. — He spoke for a nation in sorrow, but the slaughter of all those little boys and girls turned the commander in chief into another parent in grief, searching for answers. Alone on a spare stage after the worst day of his tenure, President Barack Obama declared Sunday he will use “whatever power” he has to prevent shootings like the Connecticut school massacre.

“What choice do we have?” Obama said at an evening vigil in the shattered community of Newtown, Conn. “Are we really prepared to say that we’re powerless in the face of such carnage, that the politics are too hard? Are we prepared to say that such violence visited on our children year after year after year is somehow the price of our freedom?”

For Obama, that was an unmistakable sign that he would at least attempt to take on the explosive issue of gun control. He made clear that the deaths compelled the nation to act, and that he was the leader of a nation that was failing to keep its children safe. He spoke of a broader effort, never outlining exactly what he would push for, but outraged by another shooting rampage.

“Surely we can do better than this,” he said. “We have an obligation to try.”

The massacre of 26 children and adults at Sandy Hook Elementary on Friday elicited horror around the world, soul-searching in the United States, fresh political debate and questions about the incomprehensible — what drove the 20-year-old suspect to kill his mother and then unleash gunfire on children.

A total of 6 adults and 20 boys and girls ages 6 and 7 were slaughtered.

Obama read the names of the adults near the top his remarks. He finished by reading the first names of the kids, slowly, in the most wrenching moment of the night.

Cries and sobs filled the room.

“That’s when it really hit home,” said Jose Sabillon, who attended the interfaith memorial with his son, Nick, a fourth-grader who survived the shooting unharmed.

Said Obama of the girls and boys who died: “God has called them all home. For those of us who remain, let us find the strength to carry on and make our country worthy of their memory.”

Inside the room, children held stuffed teddy bears and dogs. The smallest kids sat on their parents’ laps.

There were tears and hugs, but also smiles and squeezed arms. Mixed with disbelief was a sense of a community reacquainting itself all at once.

One man said it was less mournful, more familial. Some kids chatted easily with their friends. The adults embraced each other in support.

“We’re halfway between grief and hope,” said Curt Brantl, whose daughter was in the library of the elementary school when the shootings occurred. She was not harmed.

The president first met privately with families of the victims and with the emergency personnel who responded to the shootings. The gathering happened at Newtown High School, the site of Sunday night’s interfaith vigil, about a mile and a half from where the shootings took place.

Police and firefighters got hugs and standing ovations when they entered. So did Obama.

“We needed this,” said the Rev. Matt Crebbin, senior minister of the Newtown Congregational Church. “We needed to be together to show that we are together and united.”

Obama told Connecticut Gov. Dannel Malloy that Friday was the most difficult day of his presidency. The president has two daughters, Malia and Sasha, who are 14 and 11, respectively.

“Can we say that we’re truly doing enough to give all the children of this country the chance they deserve to live out their lives in happiness and with purpose? I’ve been reflecting on this the last few days,” the president said, somber and steady in his voice. “And if we’re honest with ourselves, the answer is no. We’re not doing enough and we will have to change.”

He promised in the coming weeks to talk with law enforcement, mental health professionals, parents and educators on an effort to prevent mass shootings.

The shootings have restarted a debate in Washington about what politicians can to do help — gun control or otherwise. Obama has called for “meaningful action” to prevent killings.

Police say the gunman, Adam Lanza, was carrying an arsenal of ammunition big enough to kill just about every student in the school if given enough time. He shot himself in the head just as he heard police drawing near, authorities said.

A Connecticut official said the gunman’s mother was found dead in her pajamas in bed, shot four times in the head with a.22-caliber rifle. The killer then went to the school with guns he took from his mother and began blasting his way through the building.

“There is no blame to be laid on us but there is a great burden and a great challenge that we emerge whole,” First Select Woman Patricia Llodra said. “It is a defining moment for our town, but it does not define us.”

Obama said his words of comfort would not be enough, but he brought them anyway, on behalf of parents everywhere now holding their children tighter.

“I can only hope that it helps for you to know,” he said, “that you are not alone in your grief.”