Treasury Secretary Steven Mnuchin on Thursday said financial companies around the world “are now on notice” about doing business with North Korea.​

​”Foreign financial institutions are now on notice​ ​that going forward they can choose to do business with the U.S or ​North Korea, but not both​,” he said, following up on President Trump’s announcement that he signed an executive order that ​targets the rogue regime and nations that do business with the country.

​He said the actions will be “forward looking” and will take effect immediately in an effort to force President Kim Jong Un to cease his “hostile behavior.”

​”​For too long, N​orth Korea ​has evaded sanctions and used the international financial system​ ​… for its ​weapons of mass destruction and ​ballistic missile programs​,​”​ he said.

Asked whether Trump issued his executive order because sanctions imposed by the United Nations on North Korea’s imports and exports failed, he said the new penalties are “significant” because they allow the US to “freeze or block any transactions with any financial institution anywhere in the world that facilitates any transactions with the blocked person.”