WASHINGTON -- The United States has issued new sanctions on four Chinese trading companies and a Chinese national said to have conducted hundreds of millions of dollars in business with North Korea.

The Treasury Department also designated six North Korean shipping and trading companies and 20 vessels as part of its efforts to disrupt funding for the rogue nation's nuclear and missile programs.

Tuesday's action comes a day after the United States returned North Korea to its list of .

Treasury Secretary Steven Mnuchin said in a statement that the U.S. is determined to "maximize pressure" to isolate North Korea from outside sources of trade and revenue.

"As North Korea continues to threaten international peace and security, we are steadfast in our determination to maximize economic pressure to isolate it from outside sources of trade and revenue while exposing its evasive tactics," Mnuchin said in a statement released by the Treasury Department.

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Those sanctioned are barred from holding U.S. assets or doing business with Americans.

A North Korean corporation was also designated for exporting laborers overseas.

The Treasury Department statement said that between January 1, 2013, and August 31, 2017, three Chinese companies cumulatively exported approximately $650 million worth of goods to North Korea and cumulatively imported more than $100 million worth of goods from North Korea.