The reply by “Sarah” to the US President’s public comment on the mass killing went viral after she urged him to introduce gun control measures instead of platitudes.
Mr Trump had tweeted his “prayers and condolences” to the families of those murdered, adding: “No child, teacher or anyone else should ever feel unsafe in an American school.”
The account chaddiedabaddie, which purports to belong to a girl attending Marjory Stoneman Douglas High School in Parkland, near Fort Lauderdale, replied: “I don’t want your condolences you f*****g price (sic) of s**t, my friends and teachers were shot.
“Multiple of my fellow classmates are dead. Do something instead of sending prayers. Prayers won’t fix this. But Gun control will prevent it from happening again.”
By Thursday morning her message had been retweeted 65,000 times and liked by more than 154,000 people.
Seventeen people were killed when a gunman – allegedly 19-year-old Nikolas Cruz – opened fire with an AR-15 semi-automatic rifle on Wednesday.
Police said a suspect was later arrested carrying several additional magazines of ammunition. They said Mr Cruz had a history of “disturbing” social media posts.
A teacher at the school said he and colleagues had been warned not to allow Mr Cruz onto campus carrying a backpack after he allegedly threatened fellow pupils.
Sarah’s account has posted a number of tweets relating to Parkland and the school in recent weeks, and she appeared to have attended a Lana Del Rey concert in Florida earlier in February.
After responding to Mr Trump’s message of condolence, she tweeted: “Today has been the worst day of my life. I’ve been crying helplessly for hours. Thank you to everyone for your support. I’m going to try to sleep now.”
Her tweet in response to the President was seized upon by several high-profile names in the entertainment industry.
Josh Gad, who became known as the voice of Olaf in Disney’s blockbuster Frozen, wrote on Twitter: “Retweet this until you are blue in the face.”
Ali A Rizvi, a Pakistani-Canadian author best known for The Atheist Muslim, said simply: “Message to Donald Trump from a Douglas High School student. #Parkland #Guncontrol”.
Another student who was in class at the time of the shooting said she “cannot unsee” the terror that unfolded before her.
Morgan Williams described on Twitter how her friends were killed as the gunman roamed through the school corridors.
She said: “I cannot stop hearing the sound of the gun as he walked down my hallway. I cannot unsee my classmates who were shot get carried out by police. I cannot unsee the bodies on the floor. Please keep in mind the horror of what we’ve gone through today. #prayfordouglas”
She added: “Never in a million years did I think I would have EVER gone through this. There is NO reason why I should have had to run past deceased friends and classmates to get to safety because there isn’t a control on how easy it is to get a gun.”
Additional reporting by agencies
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