School where 17 shot dead had sent out 'warning' about suspected shooter

WARNING, DISTRESSING CONTENT: The US school where 17 people were shot dead on Wednesday had sent out warnings about the suspected gunman and former student, according to a teacher.

Police have identified the Florida school shooting suspect as Nikolaus Cruz, a former student who was expelled from Marjory Stoneman Douglas High School in Parkland where at least 17 people were killed and dozens more injured on Wednesday afternoon (local time).

The gunman, who was believed to be armed with an AR-15-style rifle and multiple magazines of ammunition, surrendered to police without a struggle.

In the wake of his arrest, one teacher has revealed the teenage gunman had been identified as a potential threat to fellow students in the past.

“We were told last year that he wasn’t allowed on campus with a backpack on him,” math teacher Jim Gard told the Miami Herald.

“There were problems with him last year threatening students, and I guess he was asked to leave campus.”

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Mr Gard said the school administration had sent out an email warning teachers that the student had made threats against others in the past and should not be allowed on the campus with a backpack.

Another student interviewed on the scene by local media said Cruz had guns at home.

However, The Broward County School District Superintendent, told reporters that he did not know of any concerns raised about the student.

"We received no warnings," Superintendent Robert Runcie said.

“Potentially there could have been signs out there. But we didn't have any warning or phone calls or threats that were made.”

"This is a very tragic situation for everybody involved," Parkland Mayor Christine Hunschofsky told CNN.

"They were very scared and almost in shock when they came out."

Asked about security, the mayor said a police officer is always stationed at the school and there was a "single point of entry."

The shooting, one of several in the United States since the start of the year, will once again throw the spotlight on the country's epidemic of gun violence and the ready accessibility of weapons, with 33,000 gun-related deaths annually.

Since January 2013, "there have been at least 283 school shootings across the country -- which averages out to one school shooting a week," according to Everytown for Gun Safety, a non-profit group that advocates for gun control.