Florida school shooting: Teen threatens 'Round 2 of Florida'

A South Carolina teen has been taken into custody after threatening a "Round 2 of Florida tomorrow", authorities say.

On Thursday (NZ time), 17 people were killed and dozens wounded when 19-year-old Nikolas Cruz opened fire at a Florida high school.

Then on Friday (NZ Time) another young male sent a Snapchat showing him wearing a mask and holding what appears to be an assault rifle, along with the menacing message.

Spartanburg School District Three spokesperson Sherri Horton told Fox News authorities had received a tip-off from a student regarding a threat to the "safety of the students and staff of Broome High School".

Law enforcement rushed to the suspect's house and arrested him.

He allegedly said he was "joking" about the post.

"After informing the suspect and his parents of the law violation, the suspect stated his Snapchat post was just intended as a joke, and that he didn't have any serious intentions," Lieutenant Kevin Bobo told Fox News.

Sheriff's deputies located the mask and the weapon, which turned out to be a pellet gun.

The suspect has been charged with disturbing schools. He is being detained in a US Department of Juvenile Justice facility.