WASHINGTON (CBS/AP) — President Donald Trump addressed the nation a day after a mass shooting at a high school in Florida that left 17 people dead.

Authorities say 19-year-old Nikolas Cruz, a former student, shot and killed 17 people at Marjory Stoneman Douglas High School on Wednesday afternoon.

Trump said the school became a “scene of terrible violence, hatred and evil.”

“Our nation, with one heavy heart, is praying for the victims and their families,” said the president.

Florida Teen Nikolas Cruz Charged With 17 Murder Counts In School Attack

He continued, “We are all joined together as one American family and your suffering is our burden also. No teacher should ever be in danger in an American school. No parent should ever have to fear for their sons and daughters when they kiss them goodbye in the morning.”

During his address, Trump told children that they will never be alone in today’s world.

“I want to speak now directly to America’s children, especially those who feel lost, alone, confused or even scared. I want you to know that you are never alone and you never will be. You have people who care about you, who love you and who will do anything at all to protect you. If you need help turn to a teacher, a family member, a local police officer or a faith leader,” said Trump. “Answer hate with love, answer cruelty with kindness. We must also work together to create a culture in our country that embraces the dignity of life that creates deep and meaningful human connections and that turns classmates and colleagues into friends and neighbors.”

Trump said he is planning on traveling to Parkland to meet with victims’ families and first responders.

Cruz, the alleged gunman, was previously expelled from the school for disciplinary reasons.

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Cruz was an orphan — his mother, Lynda Cruz died of pneumonia Nov. 1 neighbors, friends and family members said, according to the Sun Sentinel. Cruz and her husband, who died of a heart attack years ago, adopted Nikolas and his biological brother, Zachary, after the couple moved from Long Island in New York to Broward County.

The boys were left in the care of a family friend after their mother died, family member Barbara Kumbatovich, of Long Island, said.

Unhappy there, Nikolas Cruz asked to move in with a friend’s family in northwest Broward. The family agreed, and Cruz moved in around Thanksgiving. According to lawyer Jim Lewis, who represents but did not identify the family, they knew that Cruz owned the AR-15 but made him keep it locked up in a cabinet and never saw him go to a shooting range with it. He did have the key, however.

Cruz passed a background check and legally purchased the assault weapon from a licensed dealer in February 2017, a law enforcement official familiar with the investigation but not authorized to discuss it publicly told The Associated Press on condition of anonymity.

The family is devastated and shocked, lawyer Lewis said. During the three months Cruz lived there, he was respectful and quiet but also sad over his mother’s death, Lewis told The AP.

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Cruz was getting treatment at a mental health clinic for a while, but hadn’t been there for more than a year, Broward County Mayor Beam Furr said during an interview with CNN.

Officials said they’re dissecting the suspect’s disturbing social media posts, without elaboration. But peers said they recognized Cruz from an Instagram photo posing with a gun in front of his face. The students called Cruz “weird” and a “loner” – even those who’d been friendly with him said they hadn’t seen him in more than a year since his expulsion.

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