The 19-year-old Florida school shooter was charged with 17 counts of premeditated murder Thursday morning after being questioned for hours by state and federal authorities following the deadliest school shooting in the U.S. in five years, CBS News reported.

Fifteen wounded survivors were hospitalized as bodies were recovered from inside and around Marjory Stoneman Douglas High School.

"So many signs that the Florida shooter was mentally disturbed, even expelled from school for bad and erratic behavior. Neighbors and classmates knew he was a big problem. Must always report such instances to authorities, again and again!" US President Donald Trump tweeted.

A shooting occurred Wednesday at Marjory Stoneman Douglas High School, a public school of some 3,000 students in Parkland, Florida.

The sheriff has confirmed the reports on the arrest of the suspect in this shooting. He is Nikolas Cruz (born in 1999), who was expelled from this school for disciplinary reasons.