NEWTOWN, Conn. -- A grieving Connecticut town braced itself Monday to bury the first two of the 20 small victims of an elementary school gunman and debated when classes could resume - and where, given the carnage in the building and the children's associations with it.

The people of Newtown weren't yet ready to address the question just three days after the shooting at Sandy Hook Elementary School, and a day after President Barack Obama pledged to seek change in memory of the children and six adults ruthlessly slain by a gunman packing a high-powered rifle.

"We're just now getting ready to talk to our son about who was killed," said Robert Licata, the father of a student who escaped harm during the shooting. "He's not even there yet."

Newtown officials couldn't say whether Sandy Hook Elementary, where authorities said all the victims were shot at least twice, would ever reopen. Monday classes were canceled, and the district was considering eventually sending surviving Sandy Hook students to a former school building in a neighboring town.

The gunman, 20-year-old Adam Lanza, was carrying an arsenal of hundreds of rounds of especially deadly ammunition, authorities said Sunday - enough to kill just about every student in the school if given enough time, raising the chilling possibility that the bloodbath could have been even worse.

The shooter decided to kill himself when he heard police closing in about 10 minutes into Friday's attack, Gov. Dannel P. Malloy said on ABC's "This Week."

At the interfaith service in Newtown on Sunday evening, Obama said he would use "whatever power this office holds" to engage with law enforcement, mental health professionals, parents and educators in an effort to prevent more tragedies like Newtown.

"What choice do we have?" Obama said on a stark stage that held only a small table covered with a black cloth, candles and the presidential podium. "Are we really prepared to say that we're powerless in the face of such carnage, that the politics are too hard?"

The president first met privately with families of the victims and with the emergency personnel who responded to the shooting. Police and firefighters got hugs and standing ovations when they entered for the public vigil, as did Obama.

"We needed this," said the Rev. Matt Crebbin, senior minister of the Newtown Congregational Church. "We need to be together here in this room. ... We needed to be together to show that we are together and united."

As Obama read some of the names of victims early in his remarks, sobs resonated throughout the hall. He closed by slowly reading the first names of each of the 26 victims.

"God has called them all home," he said. "For those of us who remain, let us find the strength to carry on and make our country worthy of their memory."

The first funerals were planned Monday for Jack Pinto, a 6-year-old New York Giants fan who might be buried in wide receiver Victor Cruz's jersey, and Noah Pozner, a boy of the same age who liked to figure out how things worked mechanically.

"He was just a really lively, smart kid," said Noah's uncle Alexis Haller, of Woodinville, Wash. "He would have become a great man, I think. He would have grown up to be a great dad."

With more funerals planned this week, the road ahead for Newtown - which had already started purging itself of Christmas decorations in a joyful season turned mournful - was clouded.

"I feel like we have to get back to normal, but I don't know if there is normal anymore," said Kim Camputo, mother of two children, ages 5 and 10, who attend a different school. "I'll definitely be dropping them off and picking them up myself for a while."

Jim Agostine, superintendent of schools in nearby Monroe, said plans were being made for students from Sandy Hook to attend classes in his town this week.

Newtown police Lt. George Sinko said he "would find it very difficult" for students to return to the same school where they came so close to death. But, he added, "We want to keep these kids together. They need to support each other."

Connecticut Education Commissioner Stefan Pryor said state construction employees are advising on renovating Sandy Hook, which serves grades kindergarten through four.

It wasn't just Newtown that was concerned about the next steps for its schoolchildren. Across the country, vigilance was expected to be high. In an effort to ensure student safety and calm parents' nerves, districts have asked police departments to increase patrols and have sent messages to parents outlining safety plans they assured them are regularly reviewed and rehearsed.

Teachers girded themselves to be strong for their students and for questions and fears they would face in the classroom.

"It's going to be a tough day," said Richard Cantlupe, an American history teacher at Westglades Middle School in Parkland, Fla. "This was like our 9/11 for schoolteachers."

Authorities say the gunman shot his mother, Nancy Lanza, at their home and then took her car and several of her guns to the school, where he broke in and shot his victims to death, then himself. A Connecticut official said the mother was found dead in her pajamas in bed, shot four times in the head with a .22-caliber rifle.

Federal agents have concluded that Lanza visited an area shooting range, but they do not know whether he actually practiced shooting there. Ginger Colbrun, a spokeswoman for the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, would not identify the range or say how recently he was there.

Agents determined Lanza's mother visited shooting ranges several times, but it's not clear whether she took her son or whether he fired a weapon there, Colbrun said.

A law enforcement official, speaking on condition of anonymity, said investigators are reviewing the contents of Lanza's computer, as well as phone and credit card records, in an effort to piece together his activities leading up to the shooting. The official was not authorized to discuss the details of the case.

Investigators have offered no motive, and police have found no letters or diaries that could shed light on it. They believe Lanza attended Sandy Hook many years ago, but they couldn't explain why he went there Friday. Authorities said Lanza had no criminal history, and it was not clear whether he had a job.

Lanza is believed to have used a Bushmaster AR-15 rifle in the school attack, a civilian version of the military's M-16 and a model commonly seen at marksmanship competitions. It's similar to the weapon used in a recent shopping mall shooting in Oregon.

Versions of the AR-15 were outlawed in the United States under the 1994 assault weapons ban. That law expired in 2004, and Congress, in a nod to the political clout of the gun-rights lobby, did not renew it.

In some of the first regulatory proposals to rise out of the Newtown shooting, Democratic lawmakers and independent Sen. Joe Lieberman said Sunday that military-style assault weapons should be banned and that a national commission should be established to examine mass shootings.

"Assault weapons were developed for the U.S. military, not commercial gun manufacturers," said Lieberman, of Connecticut, who is retiring next month. "This is a moment to start a very serious national conversation about violence in our society, particularly about these acts of mass violence."

Gun rights activists remained largely quiet, all but one declining to appear on the Sunday talk shows. In an interview on "Fox News Sunday," Rep. Louie Gohmert, a Texas Republican, defended the sale of assault weapons and said that the principal at Sandy Hook, who authorities say died trying to overtake the shooter, should herself have been armed.

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