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President Donald Trump announced Thursday that he had signed an executive order authorizing additional sanctions against North Korea by targeting individuals, companies and financial institutions that do business with what he called "this criminal rogue regime."

Speaking before a meeting with South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe, Trump said his goal is the "complete denuclearization" of North Korea and added that the nation led by Kim Jong Un posed a “grave threat to peace and security in our world.”

The president said that for 25 years North Korea had been allowed to get away with “abuse” of the international financial system to fund its weapons development program.

Trump noted that he'd signed the executive order just as China's central bank "has told their other banks ... to immediately stop doing business with North Korea." The president praised Chinese President Xi Jinping for the "very bold move."

Treasury Secretary Mnuchin confirmed that he did call the People's Bank of China early Thursday morning to alert them to this coming action, but skirted the question when asked if these sanctions were specifically aimed at China.

"This action is directed at everyone," Mnuchin said, calling the executive order a significant expansion of Treasury's power to target the Kim regime and those financial entities and individuals who seek to do business with it. The executive order is "forward looking," meaning Treasury will consider new designations on a "rolling basis" from Thursday on.

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Over the summer, Treasury took actions against the Bank of Dandong over concerns that it was participating in illicit financial activities with North Korea — an early signal to Chinese financial institutions of U.S. willingness to increase pressure on entities that do business with Pyongyang.

Trump's time at the United Nations General Assembly this week has been marked by his comments on North Korea and Kim, whom the president derided as "rocket man" during his address to the world body. Trump also threatened in the speech to "totally destroy North Korea" if that country persists with provocative actions.

"Rocket man is on a suicide mission," Trump said Tuesday. "The United States has great strength and patience, but if it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea."

The Trump administration has repeatedly assured that all options are on the table in dealing with North Korea, including a possible military response. On Thursday, when asked if it was still possible to negotiate with Pyongyang, Trump replied: "Why not? Why not?"

North Korean minister responds to Trump's UN speech: "I feel sorry for his aides" pic.twitter.com/dt2bARBgIA — NBC News (@NBCNews) September 21, 2017

So far, the administration has sought to pressure Pyonyang largely through forceful economic steps, including Thursday's latest action and U.N. Security Council sanctions earlier this month. U.S. ambassador to the United Nations Nikki Haley praised those United Nations efforts as "really important" in a briefing with reporters last week.

"We've basically taken and, in the words of North Korea, we have strangled their economic situation at this point," Haley said, pointing out that U.N. measures have banned 90 percent of North Korean exports. "That's going to take a little bit of time, but it has already started to take effect."

Mnuchin has also previously warned of possible additional U.S. sanctions on China, North Korea's main trading partner and a country the Trump administration has leaned heavily on to do more in curtailing aggression from Pyongyang.

North Korea, for their part, blasted Trump’s fiery U.N. address, with Foreign Minister Ri Yong-ho likening it to “the sound of a dog barking" on Wednesday.

“If he was thinking about surprising us with the sound of a dog barking then he is clearly dreaming,” Ri told reporters in North Korea’s first response to Trump’s speech. The comment references the Korean belief that dogs’ dreams make little sense, according to the South Korean news agency Yonhap.

"I feel sorry for his aides," Ri said when asked about Trump’s “Rocket Man” nickname for North Korea's leader.

South Korea's Moon, however, found optimism in Trump's "strong speech" to the General Assembly, saying Thursday before a bilateral meeting with Trump that he believes it will help change North Korea's actions.

Moon described ongoing provocations from the North as "extremely deplorable" — a word Trump described after as "very lucky" for him, harkening back to the 2016 presidential election and a comment made by Hillary Clinton describing some of Trump's supporters.

"I promise I did not tell him to use that," Trump said to laughter from the gathered delegations.