North Korea
The North Korean flag flies on a top of a building at the North Korean embassy compound in Beijing, China, March 8, 2017. REUTERS/Thomas Peter

The United States imposed sanctions on a Russian port service agency and Chinese firms on Wednesday for aiding North Korean ships and selling alcohol and tobacco to Pyongyang in breach of U.S. sanctions aimed at pressuring North Korea to end its nuclear programs.

The U.S. Treasury said in a statement China-based Dalian Sun Moon Star International Logistics Trading Co. Ltd and its Singapore-based affiliate SINSMS Pte. Ltd had netted more than $1 billion a year by exporting alcohol and cigarette products to North Korea.

The department also sanctioned Russian-based Profinet Pte Ltd and its director general, Vasili Aleksandrovich Kolchanov, for providing port services on at least six occasions to North Korean-flagged ships.

Kolchanov was personally involved in North Korea-related deals and interacted directly with North Korean representatives in Russia, the Treasury department said.

"The tactics that these entities based in China, Singapore, and Russia are using to attempt to evade sanctions are prohibited under U.S. law, and all facets of the shipping industry have a responsibility to abide by them or expose themselves to serious risks," U.S. Treasury Secretary Steven Mnuchin said in a statement.

Washington has been pressuring North Korea to give up its nuclear weapons program.

Gao Ye, legal representative of Dalian Sun Moon Star International Logistics Trading, said when asked for comment on the U.S. Treasury statement the matter was still unclear and the Chinese company had not received any notice.