NYPD Commissioner James O’Neill on Friday took issue with Donald Trump’s plan to arm teachers in order to prevent school shootings, calling the suggestion “not a good idea.”

“Let teachers teach,” O’Neill said following a keynote address at New York Law School, the New York Daily News reports.

“Having a gun is a big responsibility,” he continued. “You have issues of safeguarding the weapon, you have issues of training. This is what law enforcement does and you should leave it to law enforcement to protect the children of the city.”

The statement came after Trump this week suggested offering “a bit of a bonus” to teachers who carry concealed weapons in an effort to thwart potential school shootings. Trump on Friday also took aim at the school resource officer at Marjory Stoneman Douglas High School, who resigned Thursday after he failed to engage the shooter who murdered 17 students from Parkland, Florida last month. Trump suggested that officer was a “coward” for not confronting the killer.

But O’Neill referred to his city’s school safety officers as a “great program on how to keep the children in the 1,400 schools in New York City safe.”

“We have school safety officers — and there are 5,300 of them — and we have a uniformed task force,” O’Neill said. “Not only that, every precinct has Neighborhood Coordination Officers that work with the students and teachers in every school.”

“We have to make sure we have a good plan and New York City has a great plan,” he said.