The Trump administration has imposed new sanctions on a slew of North Korean shipping firms and Chinese trading companies.
The Treasury Department also has designated a North Korean corporation involved in exporting workers overseas.
Tuesday's action is the administration's latest push to isolate the rogue nation over its nuclear weapons development and deprive it of revenue. It comes a day after the United States returned North Korea to its list of state sponsors of terrorism.
When President Donald Trump announced the terror designation, he promised to intensify the "maximum pressure" campaign against Pyongyang with the "highest level" of sanctions yet. This is part of a rolling effort to compel North Korea to negotiate over its nuclear program, which poses an emerged threat to the U.S. mainland.
