EXCLUSIVE: Secretary of State Rex Tillerson, in an exclusive interview with Fox News, refused to rule out increased weaponization and even nuclearization of America’s East Asian allies to deter North Korean aggression.

“We’re exchanging views,” Tillerson said, while standing a few feet within what is technically North Korean territory inside what is known as the Joint Security Area.

“Nothing has been taken off the table,” he said, when asked whether he would rule out nuclearization of the peninsula, during the interview with Fox News.

Tillerson, who’s called the past 20 years of diplomacy toward North Korea a failure, has said the world needs a new strategy.

“Let me be very clear: the policy of strategic patience has ended,” said Tillerson in a later press availability in Seoul with South Korean Foreign Minister Yun Byung-se.

"If they elevate the threat of their weapons program to a level we believe requires action that option is on the table," Tillerson also said, adding the U.S. wants to avoid military conflict and hopes other measures convince North Korea to suspend its weapons programs.

President Trump, bolstering his secretary of state’s comments, tweeted Friday morning that North Korea is “behaving very badly.”

Then-candidate Donald Trump received criticism when, in a March 2016 interview with The New York Times, he said of nuclear weapons: “would I rather have North Korea have them with Japan sitting there having them also? You may very well be better off if that’s the case.”

In a tweet, Trump later denied he said more countries should have nuclear weapons. Tillerson is in the middle of a trip to Japan, South Korea and China, largely to discuss coordinated efforts to halt North Korea’s advancing nuclear and ballistic missile programs.

He travels to China Friday, after pressuring that government to further curtail the threat from its ally, calling its approach to North Korean aggression “troubling” and “inappropriate”

Fox News' Nick Kalman contributed to this report.