President Barack Obama vowed on Sunday to use all his power to stop gun massacres like the slaughter of 20 little children at a Connecticut school, saying "these tragedies must end".
Obama vented passion and anger as he told the grief-stricken community of Newtown, reeling from the unspeakable horror of Friday's rampage, that he was consoling victims of the fourth mass shooting of his presidency.
"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?" he said, as 26 candles burned next to his podium to remember the victims.
"I've been reflecting on this the last few days, and if we're honest with ourselves, the answer is no. We are not doing enough, and we will have to change."
Obama's remarks, though impassioned and appearing to set a new mission for his presidency of curtailing rampant gun violence, did not propose specific solutions, in keeping with the somber tone of the apolitical vigil service.
Heartrending sobs broke the silence as Obama slowly read the names of six adults who died trying to protect their innocent charges as gunman Adam Lanza (20) unleashed terror with a military-style assault rifle.
Later, in an incredibly poignant moment, the president read the names of the children, all aged six or seven, whose lives were taken.
"Charlotte, Daniel, Olivia, Josephine, Ana, Dylan, Madeline, Catherine, Chase, Jesse, James, Grace, Emilie, Jack, Noah, Caroline, Jessica, Benjamin, Avielle, Allison, God has called them all home....
"We can't tolerate this anymore. These tragedies must end, and to end them we must change," Obama said, implicitly rebuking those who argue that efforts to introduce more gun control laws would do little to stop killings.
"Surely, we can do better than this," the newly re-elected president said, appearing to set up a new political battle with America's powerful gun lobby with the potential to define his second term.
Obama promised to use "whatever power this office holds" to engage Americans, law enforcement and health professionals to try to prevent more tragedies like the one that struck Newtown.
"Because what choice do we have? We can't accept events like this as routine. Are we really prepared to say that we are powerless in the face of such carnage?"
Obama will face the tough task of manipulating Washington's stalemated politics to enforce change, against entrenched interests and under a constitution that enshrines gun rights.
On several occasions, for instance with his vows to close Guantanamo Bay war on terror camp, or to transform US relations with the Muslim world, Obama has set high stakes with rhetoric only to find the stated goal impossible to achieve.
Earlier, the voices of Jewish, Christian and Muslims faith leaders united in grief, at the multi-denominational prayer service, as mourners grasped for meaning amid unbearable loss.
First responders, called to Sandy Hook Elementary School after the fusillade, who arrived to find classrooms of dead children, were applauded as the crowd stood when they entered the room.
Local councilor Patricia Llodra, tried to offer solace to grieving families, who had also earlier spent several hours with Obama.
"The horror that was visited on our Sandy Hook school was not deserved, it was the angry and desperate act of a confused young man.
"I know that Newtown will prevail, that we will not fall to acts of violence. It is a defining moment for our town, but it does not define us."
Earlier, officials formally identified Lanza as the shooter who ran amok in the picture-postcard town and confirmed that he shot his mother several times in the head at the house they shared before going to his old school and embarking on a gruesome killing spree.
Lanza used his mother's Bushmaster .223 assault rifle to kill 26 people at the school, including the 20 young children, before taking his own life with a handgun as police officers closed in and sirens wailed.
Connecticut's Chief Medical Examiner Wayne Carver has said the bodies of the child victims were riddled with as many as 11 bullets, but police are yet to give a number for rounds fired.
Grief mixed with new calls on Sunday for action with Obama under rising pressure to lead a charge to renew a ban on assault weapons and fast-firing ammunition.
Senator Dianne Feinstein of California, promised to introduce a bill to ban assault weapons on the very first day of the next Congress, 3 January.
An assault weapon ban was passed in 1994 under president Bill Clinton but it expired in 2004 and was never resurrected. Obama supported restoring the law while running for president in 2008 but did not make it a priority during his first term.
Many states, including Connecticut, already have strict laws on the purchase of firearms, but with no federal statutes, there is little to stop the traffic of guns from other states where fewer restrictions apply.
However, with gun ownership protected by the constitution and firearms popular among a broad base of Americans, especially conservative Republicans, gun bans have long been seen as a vote-losing proposition.
Back in Newtown, nerves remained on edge. One Catholic church where people attended services — Saint Rose of Lima — was evacuated due to an undisclosed threat. Armed police searched a house next door.
In ways big and small, tributes were paid — from candles lit and teddy bears left at the elementary school crime scene, to gestures at the cavernous football stadiums that usually fixate Americans' attention on Sundays.
Before the day's games around the country, the National Football League had teams observe a minute's silence in memory of those killed.
Newtown was the second deadliest school shooting in US history after the Virginia Tech massacre in 2007 in which South Korean student Seung-Hui Cho shot and killed 32 people and wounded 17 others before taking his own life.
In the most notorious recent incident, a 24-year-old, James Holmes, allegedly killed 12 people and wounded 58 others when he opened fire at a midnight screening of the latest Batman movie in Aurora, Colorado, in July.