PARKLAND, Fla. (CBSDFW.COM/AP) — A shooting at a Florida high school Wednesday sent students rushing out into the streets as SWAT team members swarmed in and locked down the building.

Seventeen people were killed at Marjory Stoneman Douglas High School, according to Broward County Sheriff Scott Israel.

As of 9:00 p.m. ET, 12 of the victims had been identified but the sheriff said those names are not going to be made public yet.

The Broward County Schools Superintendent Robert Runcie announced Wednesday night, the school will be closed the rest of the week and all school-related activities are cancelled.

Grief counselors will be available for students and staff.

Fourteen people were rushed to area hospitals.

Police had a young man, identified as Nikolas Cruz, 19, in a red shirt in custody off campus around 3:45 p.m. ET.

He was a former student who was expelled from the school.

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Nikolas Cruz in police custody

Police first put him in a police cruiser, then took him out and him on a stretcher and had him taken to a hospital, according to CBS News.

Sheriff Israel said he was arrested without incident and that he used an AR-15 in the attack.

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man in custody at school shooting in FL (CBS)

Ambulances converged on Douglas High School as emergency workers appeared to be treating  wounded people on the sidewalks.

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wounded treated outside FL high school (CBS)

A parent, Cesar Figueroa, told CBS News his daughter was in the school hiding in a closet with a friend and is afraid to talk.

He said waiting to hear from her via text was the longest 20 minutes of his life.

He said his daughter heard shots fire, saw a window blown out, she screamed and ran into a closet with friends.

He said his daughter said three students were shot in classroom next to her.

He was later reunited with his daughter.

Another parent, Beth Feingold, said her daughter sent a text at 2:32 p.m. ET saying “We’re on code red. I’m fine.” But she then sent another text soon afterward saying, “Mom, I’m so scared.” The girl was later able to escape the school unharmed.

Jeiella Dodoo is a student who escaped from school.  She told CBS News a fire alarm went off near the end of class around 2:30 p.m. ET, but there had already been a drill that morning.

They started to evacuate and then they heard gun shots.

Dodoo said she thought it was an emergency exercise at first.

She and other students ran behind the school, jumped a fence and then ran to a nearby Walmart.

Florida Sen. Bill Nelson told CBS News, “This a bad day for the students, the school and their parents and thoughts and my prayers go out to the people who are grieving.”

The Broward Schools Superintendent Robert Runcie said it appears the shooter, believed to be a former student, has been apprehended.

“There are numerous fatalities.  It’s a horrific situation,” he said.

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students evacuate after high school shooting in Florida (CBS)

One student inside the building took to Twitter to document the terror.

Television footage showed police in olive fatigues, with weapons drawn, entering the school, then dozens of children running and walking quickly out.

A police officer waved the students on, urging them to quickly evacuate the school.

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SWAT team at Florida high school shooting (CBS)

Emergency medical personnel pulled stretchers from the backs of ambulances as police cars surrounded the parking lot of the Marjory Stoneman Douglas High School in Parkland.

Florida Rep. Ted Deutch told CBS News “We’ve got to come together as a community.  It’s such a heart-wrenching scene.”

The Congressman said he’d recently visited the school and talked to students in the politics club.

READ CBS MIAMI COVERAGE HERE

The White House released the following statement on the shooting Wednesday afternoon.

The President has spoken with Governor Scott of Florida and offered federal assistance if needed. Department of Homeland Security Secretary Nielsen also spoke with Governor Scott as well as state and local officials. She has briefed the President on those conversations. The Governor, the Secretary, and other Administration officials will continue to keep the President updated.

In light of this tragedy there will not be a regularly scheduled briefing as previously announced. We will inform you as more information is available.

We continue to keep the victims, and their friends and family, in our thoughts and prayers.

CBS obtained a photo of Nikolas Cruz holding a handgun.

nikolascruz Suspect In Custody After 17 Killed In Shooting At High School In Florida

Nikolas Cruz

Florida Senator Marco Rubio tweeted about the attack.

READ CBS NEWS COVERAGE HERE

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)