A senior administration official who deals with the Korea issue said the "fire and fury" comment, which was Trump's strongest warning yet for North Korea and which he delivered to reporters in New Jersey, was "unplanned and spontaneous". "But diplomatically you never like to have someone in a corner without a way for them to get out".
"It is the job of Secretary (James) Mattis as Secretary of Defence to talk about military options, and he has done so unequivocally".
Steny Hoyer, the No. 2 Democrat in the U.S. House of Representatives, said Trump's threat to North Korea "is reckless and shows a serious lack of judgment".
The plan would be put into practice at any moment, once Kim Jong Un made a decision, a Korean People's Army spokesman said.
She added: "Trump's tweet gives the misleading impression that he has already ordered concrete changes to the USA nuclear arsenal". "We'll see what happens". Critics included fellow Republican John McCain, head of the Armed Forces Committee in the U.S. Senate, who said Trump should tread cautiously.
In an interview with BBC radio, Gorka reacted to a statement by Tillerson that a conflict with the isolated communist state was not imminent and that "Americans should sleep well at night".
"I think the President just wanted to be clear to the North Korean regime on the United States unquestionable ability to defend itself [.] and its allies and I think it was important that he deliver that message to avoid any miscalculation on their part".
"Whether we've got [North Korea] backed into a corner or not is hard to say", he said.
The 17-term congressman, who also serves on the House subcommittee that oversees nuclear weapons development, said there's actually been no meaningful steps taken to improve the nation's nuclear capabilities during the Trump administration.
Asked again if Tillerson should be listened to, Nauert said, "I think that everyone has clearly heard what Secretary Tillerson's forceful comments have been and have continued to be on DPRK". He's a Cabinet secretary. "He carries a big stick".