TALLAHASSEE, Fla.: Florida’s governor announced plans Friday to put more armed guards in schools and to make it harder for young adults and some with mental illness to buy guns, responding to days of intense lobbying from survivors of last week’s shooting at a Florida high school.

Gov. Rick Scott unveiled his school safety proposals as teachers returned for the first time to Marjory Stoneman Douglas High School since the shooting nine days ago that killed 17 people.

The shooting sparked an intense push to restrict access to assault rifles fueled by student activists who swarmed the state Capitol demanding concrete gun control measures.

President Donald Trump said repeatedly Friday that he favored arming teachers to protect students, an idea many educators rejected.

“I am totally against arming teachers,” Broward schools Superintendent Robert Runcie said. “They have a challenging job as it is.”

Scott, a Republican widely expected to run for the Senate, outlined his plan at a Tallahassee news conference. In addition to banning firearm sales to anyone under 21, he called for a trained law enforcement officer for every school — and one for every 1,000 students at larger schools — by the fall 2018 school year.

Stoneman Douglas High in Parkland, which has over 3,000 students, had one armed resource officer who never entered the building while a gunman was shooting people inside, officials said.

That failure was compounded by confusion about what was being shown to police on school security cameras the day of the shooting and the lack of meaningful response to reports to the FBI and local police that 19-year-old suspect Nikolas Cruz might become violent, had guns and possibly would attack a school.

Florida’s House speaker called it an “abject breakdown at all levels.”

Cruz is jailed on 17 counts of murder and has confessed to the shootings, investigators say.

A woman close to Cruz warned the FBI on Jan. 5 that he had rifles and said, “I know he is going to explode,” according to a transcript of the tip to the FBI’s call center, which was obtained Friday by the Associated Press.

The FBI has acknowledged it failed to investigate the tip. The woman described Cruz’s short temper and said he had the “mental capacity of a 12- to 14-year-old.” She said Cruz posted pictures of weapons on social media and he wrote, “I want to kill people.”

Among other things, the governor’s $500 million plan would create a “violent threat restraining order” that would let a court prohibit a violent or mentally ill person from purchasing or possessing a firearm or any other weapon under certain circumstances.

The proposal would also strengthen gun purchase and possession restrictions for mentally ill people under the state’s Baker Act, which allows someone to be involuntarily hospitalized for up to 72 hours. Scott is seeking $50 million for mental health initiatives that include expanding mental health services by providing counseling, crisis management and other mental health services for youth and young adults.

“No one with mental issues should have access to a gun. It is common sense. It is for their own best interest, much less the best interest of our communities,” Scott said.

The governor’s plan made no mention of arming teachers. However, the Legislature’s Republican leadership proposed letting teachers carry a gun if they have had law enforcement training. The legislators’ plan also calls for a three-day waiting period for most gun purchases.

Democrats said neither plan goes far enough.