US threatens to act against any country doing trade with N Korea

US Treasury Secretary Steve Mnuchin said on Wednesday that if the United Nations does not put additional sanctions on North Korea over nuclear tests, he has an executive order ready for President Donald Trump to sign that would impose sanctions on any country that trades with Pyongyang.

"I have an executive order prepared. It's ready to go to the president. It will authorise me to stop doing trade, and put sanctions on anybody that does trade with North Korea. The president will consider that at the appropriate time once he gives the UN time to act," Mnuchin told reporters on a flight back to Washington from North Dakota, where Trump gave a speech on tax reform.

Earlier, on Wednesday, the US proposed a resolution at the UN that would include broad new sanctions on North Korea and freeze the assets of leader Kim Jong-un in the wake of global concern over the rogue nation's nuclear weapons tests.

"We believe we need to economically cut off North Korea while they do this action," Mnuchin said. Trump will consider the already-drafted executive action "if we don't get those additional sanctions at the UN", he added.

On Sunday, North Korea announced it had successfully conducted its sixth weapon test, which, according to readings of the tremors, appeared to be the most powerful weapon Pyongyang has tested. The country claimed it was a thermonuclear or hydrogen bomb.

The UN approved sanctions on the country less than a month ago, but Mnuchin said on Wednesday that additional sanctions are crucial.

Following the latest test, Mnuchin told Fox News on Sunday that he was planning to work up the sanctions executive order and recommend it to Trump.

"I am going to draft a sanctions package to send to the President for his strong consideration that anybody that wants to do trade or business with them would be prevented from doing trade or business with us," Mnuchin said at the time. "People need to cut off North Korea economically. This is unacceptable behaviour."

Also, on Sunday, Trump mentioned the possibility of "stopping all trade with any country doing business with North Korea".

And though Defence Secretary James Mattis warned of a "massive military response" to any additional threats against the United States or its allies, Trump said on Wednesday that military action in North Korea is not his "first choice" after a phone call with Chinese President Xi Jinping.