Republican presidential front-runner Donald TrumpDonald John TrumpNew Bob Woodward book will include details of 25 personal letters between Trump and Kim Jong Un On The Money: Pelosi, Mnuchin talk but make no progress on ending stalemate | Trump grabs 'third rail' of politics with payroll tax pause | Trump uses racist tropes to pitch fair housing repeal to 'suburban housewife' Biden commemorates anniversary of Charlottesville 'Unite the Right' rally: 'We are in a battle for the soul of our nation' MORE says he will not rule out using nuclear weapons against the Islamic State in Iraq and Syria.

ADVERTISEMENT

“I don’t want to rule out anything,” he said Thursday on NBC’s “Today.”

Trump noted he doesn't want to use nuclear weapons, calling them "a horror."

“The power of weaponry today is the single greatest problem that our world has, and it’s not global warming like our president said, it’s the power of weapons — in particular, nuclear," he said.

“I will be the last to use it. I will not be a happy trigger like some people might be, but I will never, ever rule it out.”

Trump has similarly refused to rule out using nuclear weapons in Europe, saying they could be used as a negotiating tool. He has also suggested arming Japan and South Korea with nuclear weapons in order to counter North Korea.