Young survivors of Wednesday's school shooting in Florida have taken part in an emotionally charged rally demanding tighter gun controls.
Protesters in Fort Lauderdale chanted "shame on you", referring to US lawmakers and President Donald Trump.
He said last year he would "never" infringe on the right to keep arms.
Suspect Nikolas Cruz has admitted carrying out the attack at the Marjory Stoneman Douglas High School in Parkland, in which 17 people died.
It was the deadliest US school shooting since 2012 and has re-ignited long-running debates about tougher firearm restrictions.
In his first public comments on the gun control issue since the attack, Mr Trump blamed the Democrats for not passing legislation when they controlled Congress during the early years of Barack Obama's administration.
Students and their parents - as well as politicians - took part in the event in Fort Lauderdale, close to Parkland. Thousands of people attended, according to the Associated Press.
Arguably the most memorable moment came when high school student Emma Gonzalez took to the podium and attacked the US president and other politicians for accepting political donations from the National Rifle Association (NRA), a powerful gun rights lobby group.
"If the president wants to come up to me and tell me to my face that it was a terrible tragedy and... how nothing is going to be done about it, I'm going to happily ask him how much money he received from the National Rifle Association," said Ms Gonzalez.
"It doesn't matter because I already know. Thirty million dollars," the 18-year-old said, referring to donations during Mr Trump's presidential campaign.
"To every politician who is taking donations from the NRA - shame on you!" said Ms Gonzalez, who took cover on the floor of her secondary school's auditorium during the attack.
Responding to her passionate speech, the crowds started chanting "Shame on you!"
According to the Center for Responsive Politics, the NRA spent $11.4m (£8.1m) supporting Mr Trump in the 2016 campaign, and $19.7m opposing Hillary Clinton.
Ryan Deitsch, who was among those hiding in a school toilet during the attack, urged lawmakers to pass more restrictive measures on gun ownership.
Mr Trump - who on Friday met survivors of the attack - earlier blamed the shooter's mental health.