President Joe Biden spoke solemnly at the White House on Tuesday night, grieving the loss of at least 19 children and two teachers, and insisting on urgent action to reform gun laws, hours after officials say a gunman killed the young students and three adults at a Texas school.

With First Lady Jill Biden, a teacher, standing behind him, Biden called on Americans to send prayers to the victims and their families, saying he knows that losing a child is like “having a piece of your soul ripped away.”

“Another massacre,” he sighed. “Beautiful, innocent second-, third- and fourth-graders. How many scores of little children who witnessed what happened. See their friends die as if they’re on a battlefield for God’s sake.”

The president spoke directly after returning to the White House Tuesday evening from a trip to meet with allies in Asia. The day he left for that trip, he had visited the site of what authorities called a racially-motivated shooting in Buffalo, making a moral call-to-action to Americans and policymakers to address the “poison” of white supremacy.

While he did call for an updated assault weapons ban in Buffalo last week, Biden on Tuesday more clearly shamed pro-gun lawmakers and lobbyists.

“Why are we willing to live with this carnage? Why do we keep letting this happen? Where in God's name is our backbone, or the courage to deal with and stand up to the lobbies?” he asked.

“It's time to turn this pain into action for every parent, for every citizen in this country. We have to make it clear to every elected official in this country: it's time to act,” he added.

Officials in Texas say the suspect who targeted the children was an 18-year-old man. They say he was later killed by police.

Federal law enforcement officials also said the death toll was expected to rise. It was the deadliest shooting at a U.S. grade school since a gunman killed 20 children and six adults at Sandy Hook Elementary in Newtown, Connecticut, almost a decade ago. 

The massacre of young children was another gruesome moment for a country scarred by an almost ceaseless string of mass killings at churches, schools and stores. And the prospects for any reform in the nation’s gun regulations seemed at least as dim as in the aftermath of the Sandy Hook deaths.

Biden on Tuesday once again called for an updated assault weapons ban, like the one he helped pass as a senator in 1994.

“The idea that an 18-year-old kid can walk into a gun store and buy two assault weapons – it's just wrong,” he said. “What in God's name do you need an assault weapon for except to kill someone?”

The president also said he had reflected on the United States’ plague of mass shootings on his flight home from Asia.

“What struck me was these kinds of mass shootings rarely happen anywhere else in the world. Why?” he asked. “They have mental health problems. They have domestic disputes in other countries. They have people who are lost. But these kinds of mass shootings never happen with the kind of frequency they happen in America.”

Vice President Kamala Harris also spoke about the shooting earlier in the evening at an awards gala in Washington, calling for “sensible public policy” to prevent similar tragedies.

“We would all say, naturally, that our hearts break. But our hearts keep getting broken,” she said. “Enough is enough. As a nation, we have to have the courage to take action and understand the nexus between what makes for reasonable and sensible public policy to ensure something like this never happens again.”

NOTE: This article has been updated to reflect the latest death toll figures.

The Associated Press contributed to this report.