Trump says he would've ran inside Florida school even without weapon

US President Donald Trump today said he would have entered the Florida school to save the students from a gunman even without a weapon as he criticised the inaction of a sheriff's deputy assigned to the school.

Last week, Trump called out the armed school resource officer who stayed outside Marjory Stoneman Douglas High School as the shooting unfolded, saying he "didn't have the courage."

Addressing a gathering of US governors at the White House, Trump said, "You know, I really believe -- you don't know until you test it -- but I really believe I'd run in there, even if I didn't had a weapon.

"I think most of the people in this room would have done that, too, because I know most of you. But the way they performed was really a disgrace," he said, criticising the armed sheriffs deputy who did not confront the shooter, an expelled student, at the school early this month who killed 17 people, mostly students.

White House press secretary Sarah Sanders later said Trump was touting his willingness to be a leader.

Asked if the President has been trained in using a handgun or firearm, Sanders said "I don't think that was the point he was making. He was saying that he would be a leader and would want to take a courageous action.

"A lot of the individuals that helped protect others that day weren't carrying firearms, which I think shows that you can be helpful in that process without it," she was quoted as saying by CNN.

Trump has signalled his support for raising the minimum age to purchase semi-automatic rifles, improving the background check system and arming teachers in the wake of the Parkland shooting.

"We have to take steps to harden our schools so that they are less vulnerable to attack. This includes allowing well-trained and certified school personnel to carry concealed firearms. At some point, you need volume. I don't know that a school is going to be able to hire a hundred security guards that are armed," he said.

Ridiculing deputy sheriffs on duty at the time of the attack, he said their performance was "disgusting".

"I got to watch some deputy sheriffs performing this week. And they weren't exactly Medal of Honour winners," Trump said.

He said the issue of mental health should be looked into.

"Here is the best example of mental health. This kid had 39 red flags. They should have known. They did know. They didn't do anything about it. That was really a bad time.

"Nobody bigger for law enforcement than I am. But between the people that didn't go into that school and protect those lives, and the fact that this should have been solved long before it happened -- pretty sad," the US President said.