A Florida high school has been locked down after a shooting, US authorities said.

The shooting happened on Wednesday afternoon at Marjory Stoneman Douglas High School in Parkland, according to the Broward Sheriff’s Office.

It was not immediately clear how many people were wounded.

Coral Springs Police said on Twitter the school was locked down and that students and teachers inside should remain barricaded until police reach them.

TV footage showed at least one person being wheeled to an ambulance while emergency workers appeared to be helping others on the pavement.

The news broadcasts also showed students running across the street.

Len Murray’s 17-year-old son, who attends the South Florida high school where shooting was reported, sent his parents a chilling text: “Mom and Dad, there have been shots fired on campus at school. There are police sirens outside. I’m in the auditorium and the doors are locked.”

Those words came at 2.30pm local time on Wednesday. A few minutes later, he texted again: “I’m fine.”

Mr Murray raced to the school only to be stopped by authorities under an overpass within view of the school buildings in Parkland.

No information was immediately given to parents, Mr Murray said. And he said he remained worried for all those inside.

“I’m scared for the other parents here. You can see the concern in everybody’s faces. Everybody is asking, ‘Have you hard from your child yet?'”