Story highlights Diplomatic efforts with North Korea "are backed by a strong military option," Tillerson said

The secretary of state spoke to CNN in an exclusive interview Friday

Washington (CNN) Tough military action against North Korea remains an option if diplomatic efforts fail to end its pursuit of nuclear weapons, Secretary of State Rex Tillerson told CNN Friday.

Asked about President Donald Trump's tweeted threat that he has a bigger and more powerful "nuclear button " than any weapons North Korean leader Kim Jong Un has at his command, Tillerson said North Korea understands that kind of rhetoric.

"I think the rhetoric that North Korea understands is that while it is our objective, and the President's been very clear, to achieve a denuclearization through diplomatic efforts, those diplomatic efforts are backed by strong military option if necessary," Tillerson said in an interview with CNN's Elise Labott.

'Not the first choice'

"That is not the first choice and the President's been clear that's not his first choice, but it is important that North Koreans as well as every regional player understand how high the stakes are, in an effort to ensure our diplomatic efforts are fully supported," Tillerson said.

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