President Trump on Friday said that the armed school resource officer who stayed outside during the school shooting last week in South Florida was either a “coward” or “didn’t react properly under pressure.”

Trump made his remarks to reporters outside the White House en route to a national gathering of conservatives in Maryland where he plans to reiterate his view that a primary strategy to counter such shootings is to arm teachers with concealed weapons.

Scot Peterson, school resource officer assigned to protect students at Marjory Stoneman Douglas High School, took a defensive position outside the school and did not enter the building while the shooter was killing students and teachers inside with an AR-15 assault-style rifle, authorities said.

“When it came time to get in there or do something, he didn’t have the courage,” Trump told reporters. “He certainly did a poor job.”

“They didn’t react properly under pressure, or they were a coward,” Trump added.

President Trump walks to board Marine One from the Oval Office last week. (Jabin Botsford/The Washington Post)

Peterson, a Broward sheriff's deputy, broke with widely accepted police practices put in place since the Columbine massacre in 1999.

Instead of waiting for backup or specially trained teams to arrive, officers are trained to pursue and eliminate the threat as soon as possible in an attempt to save lives.

Some officers involved in active-shooting incidents have described the terror that they or other officers felt during such moments as they pursued armed gunmen, who may be wielding more firepower than the responding officers.

When a gunman opened fire inside Pulse nightclub in Orlando, an off-duty officer working at the club exchanged shots with him. But that officer realized he was outgunned, holding only a handgun while the gunman had a rifle, so the officer retreated, police later said.

Broward County Sheriff Scott Israel criticized Peterson, the deputy, for his inaction, saying that he should have “killed the killer.” Instead, Israel said, Peterson took up a position outside the school during the shooting and never went inside.

Peterson, who had been with the department for more than three decades, resigned Thursday after being suspended by Israel. Attempts to reach him were unsuccessful.