WASHINGTON — President Trump tweeted new storm warnings Saturday, this time aimed at North Korea.

In a pair of late-afternoon tweets, Trump wrote that negotiations with the truculent, isolated nation had backfired, "makings (sic) fools of U.S. negotiators. Sorry, but only one thing will work!"

He didn't make clear what that "one thing" is but has been hinting for several days that the time for diplomacy has passed, leaving a military strike as the most likely option.

Trump tweeted Sunday that Secretary of State Rex Tillerson was "wasting his time" negotiating with North Korean leader Kim Jong Un.

► Oct. 6:Trump's tease: 'You'll find out' about 'the storm' that may be coming

► Oct. 1:Tillerson wasting time negotiating with 'Little Rocket Man,' Trump says

On Friday, the morning after he met with the nation's top military commanders, Trump spoke in cryptic terms about the "calm before the storm." When asked to clarify, Trump said: "You'll find out."

Later Friday, White House spokeswoman Sarah Sanders declined to clarify what Trump was hinting at.

Pentagon officials have predicted that a military clash on the Korean peninsula would likely result in civilian casualties on an enormous scale.

Follow Tom Vanden Brook on Twitter: @tvandenbrook