Former US president Barack Obama says America is "paralysed" by the Republican party and the country's powerful gun lobby, as the world reacts to a deadly shooting that claimed the lives of 19 children at an elementary school in Texas.
US authorities confirmed two adults were killed alongside children from grade two, three and four when an 18-year-old gunman opened fire at Robb Elementary School in Uvalde, around 130 kilometres from San Antonio on Tuesday.
It is the deadliest shooting in Texas history, and occurred four years after a gunman shot and killed 10 people at Santa Fe High School in Houston.
It comes less than a fortnight after nine people were killed at a grocery store in Buffalo, New York.
The attack has been widely condemned, including by US President Joe Biden, who described it as a massacre and vowed to act on gun reform.
Former US president Barack Obama, who was in power when the mass shooting at the Sandy Hook Elementary School in Connecticut occurred in December 2012, said there was a renewed urgency for America to act on gun reform.
"Nearly 10 years after Sandy Hook — and 10 days after Buffalo — our country is paralysed, not by fear, but by a gun lobby and a political party that have shown no willingness to act in any way that might help prevent these tragedies," he said.
"It's long past time for action, any kind of action. And it's another tragedy — a quieter but no less tragic one — for families to wait another day."
Former president Bill Clinton stressed the need for leaders at all levels of government to find ways to protect children and communities across the country.
"Our elected leaders at the local, state and federal levels, regardless of party, must find common-sense ways to keep our children and communities safe," Mr Clinton said.
"They can do so without touching the right to hunt, sport shoot, and keep guns for self-defence.
"Propaganda and paranoia have kept us from helping each other on this for too long. We can do — and be — better. The time to act is now."
Connecticut Senator Chris Murphy delivered an impassioned speech shortly after news of the Texas shooting broke.
"Our kids are living in fear. Every single time they set foot in a classroom, they think they're going to be next," he said.
Republican politicians also denounced the attack, but stopped short of calling for changes in how firearms are regulated and accessed.
Senate Republican leader Mitch McConnell said he was "horrified and heartbroken by reports of the disgusting violence directed at innocent schoolkids".
"The entire country is praying for children, families, teachers and staff, and the first responders on the scene," he said.
Texas Republican senator Ted Cruz offered his condolences to the children and families affected by the shooting and emergency services.
"Thank you to heroic law enforcement and first responders for acting so swiftly," he said.
The Republican Governor of Texas, Greg Abbott urged Texans to come together and support one another.
"Texans are grieving for the victims of this senseless crime and for the community of Uvalde," he said.
'It's pathetic and I've had enough'
Nearby in Dallas, Golden State Warriors NBA coach Steve Kerr used a pre-game press conference to urge US senators to act on HR8.
The proposed legislation would require background checks of anyone wanting to purchase a firearm, and has passed the lower house, but remains tabled in the senate.
"We can't get numb to this. We can't sit here and just read about it and go 'well, let's have a moment of silence, yeah go Dubs, you know, c'mon Mavs, let's go'," Mr Kerr said before a playoff game between the Warriors and Mavericks.
"Do you realise 90 per cent of Americans, regardless of political parties, want a universal background check?"
Mr Kerr has been a longtime advocate for gun control, after his father, Malcolm Kerr, was killed by a gunman in Beirut in 1984.
"We are being held hostage by 50 senators in Washington who refuse to even put it to a vote despite what we, the American people want," he said.
"They won't vote on it because they want to hold on to their own power.
US singer-songwriter Taylor Swift said the Uvalde shooting filled her with rage and grief, sharing Kerr's impassioned speech.
"Steve's words ring so true and cut so deep," she wrote on Twitter.
Basketball great LeBron James also took to social media to condemn the shooting, tweeting that "there simply has to be change".
"Like when is enough enough man!!! These are kids and we keep putting them in harms way at school … where it's supposed to be the safest!" he wrote.
American actor George Takei took to Twitter to criticise Mr Cruz and Mr Abbott, who are both scheduled to speak at an National Rifle Association (NRA) conference in nearby Houston on Friday, along with former US president Donald Trump.
"If Ted Cruz and Greg Abbott really cared about the children who were killed in Texas today, they would cancel their speaking gigs at the NRA conference in Houston this coming Friday," he wrote.
"If we want change, we must demand it from our leaders," he said in a separate tweet.
Poet Amanda Gorman, who spoke during Mr Biden's inauguration last year, wrote that failing to act on repeated shootings targeting children was a sign of "inhumanity".
"It takes a monster to kill children," she wrote on Twitter.
"But to watch monsters kill children again and again and do nothing isn't just insanity — it's inhumanity.
"The truth is, one nation under guns. What might we be if only we tried. What might we become if only we'd listen."
