The sanctions are part of a broader US effort to disrupt the flow of cash funding North Korean weapon's programs and target companies that have dealt in natural resources such as coal and minerals or engaged in financial transactions for North Korean interests.
"It is unacceptable for individuals and companies in China, Russia, and elsewhere to enable North Korea to generate income used to develop weapons of mass destruction and destabilize the region," Treasury Secretary Steven Mnuchin said in a statement.
The move follows a war of words between Washington and Pyongyang over recent missile tests that show North Korea is capable of reaching the US mainland.
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President Donald Trump earlier this month said he would respond to North Korea's nuclear threat with "fire and fury."
Also this month, Russia and China both voted to toughen UN sanctions on North Korea.
Trump has urged Beijing, North Korea's only major ally, to bring greater pressure to bear in reigning in the reclusive state's nuclear efforts, suggesting that the United States may offer concessions on trade in return.
Targets of sanctions
The sanctions unveiled Tuesday effectively block those targeted from accessing much of the global financial system and freeze any US assets as well.
Among those hit by the sanctions was Russian national Ruben Kirakosyan and his Moscow-based company Gefest-M LLC, which the Treasury Department accuses of procuring metals for a sanctions-barred company involved in North Korea's nuclear weapons program known as Korean Tangun Trading Corp.
Also targeted is China's Dandong Rich Earth Trading Co. Ltd., which the United States says has acted on behalf of North Korea's General Bureau of Atomic Energy -- responsible for the North's nuclear program -- and has facilitated prohibited North Korean exports of vanadium ore.
A third company, Mingzheng International Trading Limited, which maintains offices in Hong Kong and mainland China, was in fact a front for Foreign Trade Bank, North Korea's main foreign exchange bank, the Treasury Department said.
The Treasury Department said three Chinese companies -- Dandong Zhicheng Metallic Materials Co. Ltd., JinHou International Holding Co. Ltd., and Dandong Tianfu Trade Co. Ltd -- had collectively imported nearly a half billion dollars' worth of North Korean coal between 2013 and 2016.
The department also sanctioned Dandong Zhicheng's director Chi Yupeng, a Chinese national accused of moving cash for North Korean interests.
Federal prosecutors suspect the company may be involved in money laundering in support of Pyongyang, according to The Wall Street Journal.
The Treasury targeted three Russians -- Mikhail Pisklin, Andrey Serbin and Irina Huish -- accusing them of trading in fuel on behalf of North Korea through companies based in Sinagpore.
The sanctions also hit an affiliate of a Pyongyang company, Mansudae Overseas Project Group, accusing the subsidiary of exporting workers to build statues in foreign countries as a revenue source for the North.
