Hundreds of thousands of teenagers and their supporters have rallied in the US capital and cities across America to press for gun control in one of the biggest youth protests since the Vietnam era.
"If you listen real close, you can hear the people in power shaking," David Hogg, a survivor of the Florida school shooting who has emerged as one of the student leaders of the movement, told the roaring crowd of demonstrators at the March for Our Lives rally in Washington.
He warned: "We will get rid of these public servants who only care about the gun lobby."
Chanting "Vote them out!" and bearing signs reading "We Are the Change", "No More Silence" and "Keep NRA Money Out Of Politics", the protesters packed Pennsylvania Avenue between the Capitol and the White House.
Large rallies with crowds estimated in the tens of thousands in many cases also unfolded in Boston, New York, Los Angeles, Chicago, Houston, Fort Worth, Minneapolis, and Parkland, Florida, the site of the February 14 attack at Marjory Stoneman Douglas High School that left 17 people dead.
Protesters denounced the National Rifle Association and its allies and complained that they were scared of getting shot in school and tired of inaction by grown-ups after one mass shooting after another.
They called for such measures as a ban on high-capacity magazines and assault-type rifles like the one used by the Florida killer, tighter background checks and school security, and a raising of the age to buy guns.
"I'm really tired of being afraid at school," said Maya McEntyre, a 15-year-old high school freshman from Michigan, who joined a march by thousands in Detroit.
"When I come to school, I don't want to have to look for the nearest exit."
She added: "I want to get to the problem before it gets to me."
Ben Stewart, a 17-year-old senior at Shiloh Hills Christian School in Kennesaw, took part in a march in Atlanta to press for what he called "common-sense gun laws".
"People have been dying since 1999 in Columbine and nothing has changed. People are still dying," he said. "It could be prevented."
President Donald Trump was in Florida for the weekend. As of early afternoon, he had yet to weigh in on Twitter about the protests.
The NRA went silent on Twitter in the morning, in contrast to its reaction to the nationwide school walkouts against gun violence on March 14, when it tweeted a photo of an assault rifle and the message "I'll control my own guns, thank you."
About 30 gun-rights supporters staged a counter-demonstration in front of the FBI headquarters in Washington, standing quietly with signs such as "Armed Victims Live Longer" and "Stop Violating Civil Rights".
The Reverend Martin Luther King Jr's nine-year-old granddaughter Yolanda Renee King gave a rousing speech at the Washington rally, drawing from the civil rights leader's most famous words.
"I have a dream that enough is enough," she said. "That this should be a gun-free world. Period."
In Parkland, the police presence was heavy as more than 20,000 people filled a park near the school, chanting slogans and carrying signs that read "Why do your guns matter more than our lives?" and "Our ballots will stop bullets".
Gun violence was also fresh for some in the Washington crowd: Ayanne Johnson of Great Mills High in Maryland held a sign declaring, "I March for Jaelynn", honouring Jaelynn Willey, who died on Thursday, two days after being shot by a classmate at the school. The classmate also died.
