Speaking to reporters during a surprise visit to Guam Wednesday, Secretary of State Rex Tillerson reassured Americans that they should not be concerned about North Korea’s most recent threats of attack against Guam and defended the President’s “fire and fury” comments.

He said President Donald Trump is just “sending a message in language Kim Jong-un can understand.”

“The global community has expressed its view that North Korea needs to stand down this program. I think in response to that the North Korean’s rhetoric has ratcheted up louder and louder and more threatening,” he said. “So I think what the President is doing is sending a strong message in language that Kim Jong-un can understand because he doesn’t seem to understand diplomatic language.”

Tillerson’s comments come after reports surfaced that North Korea now has a nuclear warhead small enough to fit into a ballistic missile.

Speaking to reporters Tuesday, Trump said North Korea’s threats of nuclear warfare would be “met with fire and fury like the world has never seen.”

Jong-un then responded with threats of attack against Guam.

But Tillerson defended the President’s message, saying Trump was just trying to be clear to the North Korean regime that “the U.S. has an unquestionable ability to defend itself, will defend itself and its allies. I think it’s important he deliver that message to avoid any miscalculation on their part.”

He also said that there is nothing to indicate that the situation in North Korea has dramatically changed in the last 24 hours and that “Americans should sleep well at night.”

“I have no concerns about this particular rhetoric of the last few days. I think the President again, as commander-in-chief, he felt it necessary to issue a very strong statement directly to North Korea,” he said.