US President Donald Trump has said arming teachers could prevent school shootings like that which left 17 people dead last week in Florida.
A staff member with a gun could end an attack “very quickly”, he said.
Mr Trump floated the proposal as emotional survivors of the 14 February massacre implored him to make sure it never happens again.
The Republican president also backed calls for improved background checks for gun buyers.
Other survivors meanwhile lobbied Florida lawmakers on gun control.
“We’ll be very strong on background checks, very strong emphasis on the mental health of somebody,” Mr Trump told the students from Marjory Stoneman Douglas High School during Wednesday’s televised event at the White House.
“It’s not going to be talk like it’s been in the past,” he added. “It’s been going on too long, too many instances, we’re going to get it done.”
The US president also endorsed a proposal that has long been backed by the National Rifle Association (NRA), a powerful gun lobby group.
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He pledged to look “very strongly” at calls for educators to be armed with guns.
“If you had a teacher who was adept at firearms,” he said, “they could very well end the attack very quickly.”
“Where a teacher would have a concealed gun on them,” he said, while acknowledging the plan was controversial, “they would go for special training and they would be there, and you would no longer have a gun-free zone.
“A gun-free zone, to a maniac, because they are all cowards, a gun-free zone is, ‘let’s go in and let’s attack.'”
Mr Trump listened to pleas for change from about 40 students, teachers and families during the session in the executive mansion’s state dining room.
Andrew Pollack, whose daughter, Meadow, died in the Parkland attack – the second-deadliest shooting at a US public school – vented his anger.
“We’re here because my daughter has no voice,” said Mr Pollack.
“She was murdered last week and she was taken from us – shot nine times on the third floor. We, as a country, failed our children.”
“I’m pissed!” he added.
Hundreds of teenagers from the Washington DC suburbs rallied outside the White House before Mr Trump’s meeting.
Meanwhile, survivors of the shooting poured into the Florida state capital to demand lawmakers restrict sales of assault rifles.
“We want gun reform. We want common sense gun laws,” said Delaney Tarr in Tallahassee.
The students chanted “protect our kids” and carried banners with the words “never again” emblazoned across them.
It was the first organised protest of the youth-led anti-gun movement that has swept the US since the attack in Parkland.
Some lawmakers in the state legislature said they would consider raising the minimum age to buy assault rifles – like the one allegedly used in last week’s massacre – from 18 to 21.
However, on Tuesday they rejected a call to ban such weapons.
Other students across the US – including in Chicago, Illinois; Pittsburgh, Pennsylvania; and Phoenix, Arizona – walked out of classes in solidarity.
Mr Trump’s listening session came a day after he directed his administration to take steps to ban gun “bump stocks”.
The accessories – which enable a rifle to shoot hundreds of rounds a minute – were used by a gunman who killed 58 concert-goers in Las Vegas last October.
That was the deadliest attack by a lone gunman in US history.
The NRA – which contributed an estimated $30m (£21m) to help elect Mr Trump – opposes a total ban on bump stocks, but has said it is open to restrictions on the devices.