Washington (CNN) President Donald Trump said Friday that mass shootings have been "going on too long in our country" as he offered his first public remarks on the school shooting in Santa Fe, Texas.

"Unfortunately, I have to begin by expressing our sadness and heartbreak over the deadly shooting at Santa Fe High School in Texas," Trump said Friday from the East Room of the White House. "This has been going on too long in our country. Too many years. Too many decades now."

Trump said federal authorities are coordinating with local officials.

"We grieve for the terrible loss of life and send our support to everyone affected by this absolutely horrific attack," Trump said.

On Friday afternoon, Trump ordered flags at half-staff in memory of the victims "of the terrible act of violence."

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