He also said China’s central bank is ordering financial institutions to stop dealing with Kim Jong Un’s regime.
Mr Trump said the measures are intended to disrupt critical North Korean shipping and trade networks by targeting any entity that does business with the nation.
“Foreign banks will face a clear choice: Do business with the United States or facilitate trade with the lawless regime in North Korea,” he said. “The regime can no longer count on others to facilitate its trade and banking activities.”
Mr Trump praised China’s President Xi Jinping for a “very bold move” in acting to cut off financial ties with North Korea and said it was “somewhat unexpected”.
People’s Bank of China posted a notice earlier this month directing financial institutions to stop opening accounts for clients on UN sanctions lists and suspend financial trading and providing export-related credit services for those clients.
Mr Trump announced the US sanctions order at the start of a luncheon meeting in New York with South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe, key US allies in the region.
Mnuchin: "We call on all countries around the world to join us by cutting off all trade and financial ties to North Korea." pic.twitter.com/WTIsx8SqZB— ABC News Politics (@ABCPolitics) September 21, 2017
The US had warned it may impose additional sanctions on China to further squeeze the regime of Kim Jong Un.
The UN Security Council this month approved another round of sanctions that seek to cut North Korea’s imports of refined petroleum products to 2m barrels a year, ban textile exports, and strengthen inspections of ships that are believed to be carrying cargo in breach of sanctions. But to avert a threatened veto by China and Russia, the action stopped short of a US demand for a total oil embargo and a freeze on Mr Kim’s assets.
In his speech to world leaders earlier this week, Mr Trump declared that “Rocket Man,” as he derisively called the North Korean leader, is on a “suicide mission” by continuing to test and develop weapons systems.