President Trump told a group of school-shooting survivors at the White House that arming teachers may be the answer to preventing future massacres.

“A gun-free zone is, ‘Let’s go in, and lets attack because bullets aren't coming back at us,’” Trump told a group that included students who survived last week’s high school shooting in South Florida that killed 17 people.

"You can't have 100 security guards in Stoneman Douglas [High School]," Trump said at the Wednesday afternoon event.

“It's certainly a point that we will discuss, concealed carry for teachers and for people of that type of talent, let's say we had 20 percent of your teaching force, because that's pretty much the number,” he said.

“You'd have a lot of people who would be armed, who would be ready,” Trump said. “They may be Marines that left the Marines, left the Army, left the Air Force, and they are very adept at doing that. You’d have a lot of them and they would be spread evenly throughout the school.”

Trump said armed teachers could end a shooting earlier than first-responders, who sometimes arrive after the gunman is finished.

“If these cowards knew” that teachers were armed, Trump said, “I don’t think they would go into the school to start with, I think it could very well solve the problem.”

Trump also spoke of tightening background checks, rethinking age requirements to buy certain weapons, and bringing back insane asylums. He polled the room of survivors and the relatives of victims and acknowledged mixed views on arming teachers.

Mark Barden, the father of an elementary school student murdered in the 2012 Sandy Hook massacre in Connecticut, spoke against the idea, telling Trump a would-be mass murderer “is not going to care if there’s someone there with a gun” working at the school.