President Donald Trump on Tuesday said North Korea’s new alleged nuclear capabilities “will be met with fire and fury like the world has never seen.”

Asked about reports that North Korea has successfully produced a nuclear warhead small enough to fit into an intercontinental ballistic missile, Trump told reporters that he would meet the threat with “power.”

“They will be met with fire and fury like the world has never seen,” Trump said. “He has been very threatening, beyond a normal state, and as I said they will be met with fire and fury and, frankly, power the likes of which this world has never seen before.”

Asked to clarify Trump’s comments, senior White House adviser Kellyanne Conway said, “No, I can’t. I think the President’s comments were very strong and obvious.”

The Washington Post first reported on Tuesday that U.S. intelligence officials at the Defense Intelligence Agency concluded North Korea has produced a nuclear weapon small enough to fit in a missile.

After North Korea test-fired an ICBM in July, analysts concluded that a wide swath of the United States, including Los Angeles and Chicago, was within striking range.

This post has been updated.