An armed officer who stood outside a Florida school where a gunman killed 17 people last week “certainly did a poor job”, the US president has said.
Deputy Scot Peterson resigned after an investigation found he failed to confront the suspect.
President Trump said the officer trained his whole life but “certainly did a poor job” protecting students.
Mr Trump said Mr Peterson was a “coward” who “didn’t react properly under pressure”.
“He trained his whole life but when it came time to do something he didn’t have the courage,” Mr Trump told reporters outside the White House on Friday. “He certainly did a poor job.”
This week the president proposed arming teachers as a solution to school safety, a method that has long been championed by the powerful National Rifle Association (NRA) gun lobby.
Mr Trump touted his love for the second amendment, which protects gun rights, while speaking at the Conservative Political Action Conference (Cpac) on Friday morning.