North Korean leader Kim Jong Un watches the launch of his country's own Hwasong-12 missile in this undated photo released by North Korea's Korean Central News Agency (KCNA) on September 16, 2017.

President Donald Trump issued a veiled new threat to North Korea on Saturday, saying years of diplomacy and financial incentives have failed to sway the regime but "only one thing" could — once again suggesting the U.S. was all but prepared for the growing possibility of an armed confrontation.

Just days after declaring attempts to negotiate with the regime were a "waste," and the U.S. was prepared to "do what has to be done," the president said via a series of Twitter posts that efforts to persuade Pyongyang to drop its aggression were ineffective.

North Korea has steadily tested a series of weapons, in defiance of international pressure and the threat of new sanctions. Disparaging decades of financial and diplomatic measures that had yet to alter the trajectory of the standoff with North Korea, Trump exclaimed that "sorry, but only one thing will work!"

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Trump's comment on Saturday came on the heels of a cryptic remark the president made during a photo-op with several military members. The president mentioned to reporters that the gathering could represent the "calm before the storm," yet failed to elaborate further.

Last week, Secretary of State Rex Tillerson said that the U.S. had opened a direct channel of communication with Pyongyang, which has tested rockets with increasing regularity. Tillerson has said there were at least "a couple" of channels through which the two parties were attempting to negotiate.

Yet Trump on Sunday effectively undercut his chief diplomat by declaring negotiations to be all but fruitless. Trump told Tillerson to "save his energy," suggesting the U.S. was prepared to escalate its heated rhetoric to potential military action.

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Trump has steadily lobbed rhetorical salvos at North Korean leader Kim Jong Un, which culminated last month at a speech at the United Nations. The president has taken to calling Kim "Rocket Man," in light of his insistence on firing rockets, a moniker he used at the world body when he said the U.S. would "totally destroy" North Korea, if provoked.

He also caused a stir over the summer when he said America would rain down "fire and fury" on the country if it continued its provocations.

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Against the backdrop of a possible conflagration on the Korean Peninsula is the speculation swirling around Tillerson. Earlier this week, NBC News reported that Tillerson had privately disparaged his boss, and had even considered resigning. Trump blasted the report as "fake news," yet it hasn't diminished concerns about a rift between the president and America's senior diplomat.