Washington is ready to use “any appropriate measures” to defeat the growing threat from North Korea, according to one of President Donald Trump‘s key aides.

Sebastian Gorka, who is deputy assistant to the president, said on Thursday that the White House will use any means necessary to defend the United States and its citizens from military attack, but insisted that the administration would not disclose these measures ahead of time.

“Donald Trump has been unequivocal: he will use any appropriate measures to protect the United States and her citizens,” Gorka told the BBC’s “Today” program.

Criticizing the former Obama administration for being too open in its diplomatic discourse, Gorka said that Washington would continue to keep its cards close to its chest until North Korea shows signs of acting on its continued threats of nuclear act. North Korea announced on Wednesday that it plans to launch a missile test on the U.S. military base of Guam.

“We do not telegraph our future scenarios and how we are going to react. That’s how the Obama administration thought strategy works. That’s not how it works,” insisted Gorka.

“If you show players around a table your poker hand, you will lose that game. It is not a good idea in cards; it is a very bad idea in geopolitics. We have sent a very clear message: do not challenge the United States because you will pay a cost if you do so. Any other details are classified and will remain so,” he added.

The Trump administration has come under scrutiny for its response to Kim Jong Un’s threats however, with critics saying its lack of clarity could serve to escalate tensions.

Earlier this week, Trump warned North Korea about facing “fire and fury” if the isolated nation makes more threats against the U.S.

On Wednesday, Trump touted the U.S. nuclear arsenal on Twitter but said he hopes “he will never have to use it.”

“My first order as president was to renovate and modernize our nuclear arsenal. It is not stronger and more powerful than ever before,” Trump claimed in a Tweet. “Hopefully we will never have to use this power, but there will never be a time that we are not the most powerful nation in the world,” he added.

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