US President Donald Trump has said he would have run in to the Florida high school where 17 people were shot dead this month even if he was not armed.
"I really believe I'd run in there even if I didn't have a weapon," Mr Trump told a group of state governors gathered at the White House.
Mr Trump also said it was "disgusting" that officers reportedly did not confront the suspect on 14 February.
The massacre was the second-deadliest ever shooting at a US school.
"I think most of the people in this room would have done that, too," said Mr Trump on Monday of his assertion that he would have rushed into the school.
He added: "You never know until you're tested."
His comments came after Florida governor Rick Scott on Sunday launched an inquiry into law enforcement's response to the massacre at Marjory Stoneman Douglas High School.
Scot Peterson, a 32-year veteran officer who had been assigned to guard the high school, resigned last week as it emerged he had remained outside the building where most of the pupils were killed.
What has the school officer said?
Mr Trump had previously suggested that the actions taken that day by Mr Peterson - who has since resigned from the force - could have made him a "coward".
But on Monday, a lawyer for Mr Peterson hit back against Mr Trump's claim, saying his client had been "maligned" by his previous boss, Sheriff Scott Israel.
"Let there be no mistake, Mr Peterson wishes that he could have prevented the untimely passing of the seventeen victims on that day, and his heart goes out to the families of the victims in their time of need," his lawyer Joseph DiRuzzo III said in a statement provided to the BBC.
"However, the allegations that Mr Peterson was a coward and that his performance, under the circumstances, failed to meet the standards of police officers are patently untrue.
"Mr Peterson is confident that his actions on that day were appropriate under the circumstances and that the video (together with the eye-witness testimony of those on the scene) will exonerate him of any sub-par performance," the lawyer's statement said.
Mr DiRuzzo said Mr Peterson believed the shooting was occurring outside the building and "initiated a Code Red lockdown of the entire school campus".
He also provided "handwritten diagrams" of the school to responding Swat officers, according to the lawyer.
What has the Broward County sheriff said?
Sheriff Israel has defended himself from criticism amid calls for his resignation, saying that he should not be blamed for the actions of a rogue "deserter".
"I've given amazing leadership to this agency," he said during a CNN interview on Sunday, insisting that he has no plans to quit.
Broward County Sheriff's Office is reportedly also investigating why three of its deputies appeared to remain outside the building with their guns drawn as the attack unfolded.
Mr Trump criticised those officers as well, saying they "weren't exactly medal of honour winners"- a reference to the US military award for valour.
"The way they performed was frankly disgusting," Mr Trump added.
What has Mr Trump proposed as a solution?
In the wake of the attack, which was carried out by a former student, Mr Trump has called for US teachers to be trained and armed with concealed firearms.
He also suggested that teachers receive a "yearly bonus" for carrying guns, but in a tweet, conceded that such a decision should be "up to states" to legislate.
Mr Trump has also pushed for expanded background checks and mental health screenings in order to legally purchase a gun, and suggested raising the legal age requirement to buy a semi-automatic rifle.
The president has also called for so-called bump stocks - which convert rifles into machine guns - to be banned under federal law.
During his remarks on Monday, Mr Trump told governors not to "be afraid" of clashing with the National Rifle Association (NRA) - a powerful pro-gun lobby which has opposed several of Mr Trump's proposals.
"Don't worry about the NRA, they're on our side," he said.
"And you know what, if they're not with you, we have to fight them every once in a while. That's OK. They're doing what they think is right."
In Florida, students are preparing to return full-time to their classrooms on Wednesday after some attended a volunteer "orientation" on Sunday.
"It's like the first day of school," a 16-year-old girl in attendance told the New York Times.
"But it's not normal at all."