US President Joe Biden has delivered an emotional call for new restrictions on firearms after a gunman opened fire at a Texas primary school, killing 18 children.
"When in God's name are we going to stand up to the gun lobby?" a visibly shaken Biden said at the White House shortly after returning from a five-day trip to Asia that was bookended by tragedy.
With first lady Jill Biden standing by his side, Biden said, "I am sick and tired. We have to act.
"It's time we turned this pain into action."
At least 18 students were killed in Texas, according to a state senator who said he was briefed by law enforcement. One teacher was killed, as was the gunman.
"To lose a child is like having a piece of your soul ripped away," Biden said.
"There's a hollowness in your chest. You feel like you're being sucked into it and never going to be able to get out."
Just two days before Biden left on his trip, he met with victims' families after a hate-motivated shooter killed 10 Black people at a grocery store in Buffalo, New York.
The back-to-back tragedies served as sobering reminders of the frequency and brutality of a US epidemic of mass gun violence.
"These kinds of mass shootings rarely happen anywhere else in the world," Biden said. "Why?"
It is unclear whether the latest tragedy will change the political dynamic around guns after so many others - including the 2012 shooting at Sandy Hook Elementary School in Connecticut that killed 26, including 20 children - failed to do so.
In a reminder of the issue's divisiveness, Biden's call for gun control on Tuesday was booed at a campaign event in Georgia hosted by Herschel Walker, a Republican running for US Senate.
Vice President Kamala Harris said earlier people normally declare in moments like this, "our hearts break. But our hearts keep getting broken ... and our broken hearts are nothing compared to the broken hearts of those families".
"We have to have the courage to take action ... to ensure something like this never happens again," she said.
Shortly before landing in Washington, Biden spoke with Texas Governor Greg Abbott from the presidential plane "to offer any and all assistance he needs in the wake of the horrific shooting", White House communications director Kate Bedingfield tweeted.
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