Florida shooting: 17 dead in 'absolutely pure evil' high school massacre in Parkland - as it happened

Seventeen people have been killed and more than a dozen injured after a gunman opened fire at a Florida high school.

Aerial footage showed students streaming out of the school with their hands in the air before dropping their backpacks into a large pile next to police and sitting on nearby grass. Parents were instructed to meet at a location away from the school, where they waited anxiously to be reunited with their children.

The carnage began shortly before school was to be let out at 2.40 pm, when the sound of gunfire ripped through the air.

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Sheriff Scott Israel of Broward County said the 19-year-old suspect - identified in media reports as Nikolaus Cruz - is in custody and that investigators are beginning to "dissect" what happened in the attack.

Marjory Stoneman Douglas High School in Parkland, about 45 miles (72 km) north of Miami, was placed on a “code red” lock down, and students tweeted and texted from inside about the chaos that had come down upon their school.

Of the fatalities, 12 were killed inside the school, two were killed outside on the campus grounds, one was killed on a road outside of the school, and another two were transported to the hospital but died there.

Sheriff Israel said the suspect, a former student, was previously expelled for disciplinary reasons. Mr Israel added that the gunman had at least one rifle - believed to be an AR-15 - and multiple magazines.

The White House has cancelled its daily press briefing and President Donald Trump has spoken with Florida Governors Rick Scott about the shooting. He said in a tweet that the White House is “working closely with law enforcement on the terrible Florida school shooting.”

He earlier tweeted his condolences to the families of the victims.

Spokeswoman Sarah Huckabee Sanders said Mr Trump has offered Florida federal assistance, if needed. The homeland security secretary has also been in touch with state and local officials.

Ms Sanders said, “We continue to keep the victims, and their friends and family, in our thoughts and prayers.”

Agencies contributed to this report