Students and teachers who survived a mass school shooting in Florida have issued emotional and urgent calls for gun control at a rally.

A crowd of at least one thousand people gathered in front of the federal courthouse in Fort Lauderdale, giving impassioned speeches referencing the dead and demanding tougher gun laws. Seventeen students and teachers were killed when an assailant opened fire at Marjory Stoneman Douglas High School this week.

Chants of “enough is enough!” and “No more guns!” reverberated though the gathering. People lofted signs carrying messages like and “protect lives not guns”.

“This isn’t just a mental health issue. He wouldn’t have hurt that many students with a knife,” student Emma Gonzalez said of the assailant, her voice quavering with outrage as she challenged Donald Trump’s tweet noting “so many signs” the alleged killer was “mentally disturbed”.

“If the president wants to come up to me and tell me to my face that it was a terrible tragedy and how it should never have happened and maintain telling us how nothing is going to be done about it,” Ms Gonzalez said to a roaring audience, “I’m going to happily ask him how much money he received from the National Rifle Association”.

She led the crowd in chants of “shame on you!” after referencing politicians accepting National Rifle Association donations.

Florida shooting – in pictures Show all 10 1 /10 Florida shooting – in pictures Florida shooting – in pictures Police arrest a suspect in connection with the shooting at the Marjory Stoneman Douglas High School in Parkland, Florida Reuters Florida shooting – in pictures Parents wait for news after reports of a shooting at Marjory Stoneman Douglas High School in Parkland, Florida AP Florida shooting – in pictures Anxious family members wait for news of students AP Photo/Wilfredo Lee Florida shooting – in pictures Students being evacuated from the school AP Florida shooting – in pictures Students being evacuated from the school Getty Florida shooting – in pictures People gather waiting for word from students AP Florida shooting – in pictures Parents waiting for news on their children AP Florida shooting – in pictures People gather at a hotel where students were taken after the shooting Getty Florida shooting – in pictures Florida Governor Rick Scott speaks to the media as he visits Marjory Stoneman Douglas High School following the shooting AFP/Getty Florida shooting – in pictures Dr. Igor Nichiporenko, Medical Director Trauma, left, and Dr. Evan Boyer, Medical Director, Emergency Services, speak about treating victims and the suspect at a press conference outside Broward Health North hospital AP

Fighting back tears, teacher Melissa Falkowski recounted surviving the horror.

“No teacher should have to be huddle in a closet with her students to keep them calm”, she said.

Multiple speakers called on their elected officials, both in the state capital in Tallahassee and in Washington, to enact tougher gun control measures like a ban on assault weapons. The shooter used an AR-15, a common type of semiautomatic rifle.

“It is well past time that no civilians have access to an AR-15,” Broward Teachers Union president Anna Fusco said. “It is time for action now. It is time for more than thoughts and prayers…It’s well past time we do extreme vetting when it comes to guns,” she added, referencing Mr Trump’s call for “extreme vetting” of immigrants.

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Rep Ted Deutch echoed the call to outlaw assault weapons, adding that Congress should ban high-capacity magazines, expand background checks and raise the minimum age for buying rifles from 18 to 21.

Speakers called on attendees to translate their grief and anger into political change.