Betsy DeVos said schools have the “option” of arming teachers but refused to be drawn on whether she personally believed it was a good idea.

Speaking after 14 students and three staff members were killed in a Florida high school, the US education secretary said individual states and cities needed to decide for themselves whether teachers should be trained in the use of guns.

“I think this is an important issue for all states to grapple with and to tackle,” she told conservative radio host Hugh Hewitt. “They clearly have the opportunity and the option to do that, and there are differences in how states approach this.

“I think this needs to be part of the broader, more robust conversation about how can we avoid these things in the future, and how can we ensure that when my child, your child, goes to school in the morning they’re going to go to a safe and nurturing environment, and they’re going to be able to pursue their learning in a way that is going to excite and energise them.”

“I think that is a question and issue for communities to wrestle with, and I’ve seen approaches in different cities done different ways.

“It is one that has to happen at the local level and at the state level. Communities need to share best practices and results from the steps that they take to ensure that kids have a safe environment in which to learn.”

DeVos added that she was “heartbroken” by Wednesday’s massacre and that “there have been far too many of these situations”.

The gunman has been charged with 17 counts of murder at the Marjory Stoneman Douglas High School in the city of Parkland.

the US education secretary told Hewitt that the high school shooter, Nicolas Cruz, had “put up lots and lots of signals and warning signs” ahead of the attack.

She said: “I think it’s critically important that we have a much more robust conversation around tracking and tackling mental health issues and really bringing this all together.

“Congress needs to be holding hearings on these issues. We’ve seen lots of discussion about this every time we’ve had another incident, we’ve seen lots of finger-pointing back and forth. But we need to have a conversation at the level where lawmakers can actually impact the future.”