TOPSHOT - US President Donald Trump (R) poses with North Korea's leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. - Donald Trump and Kim Jong Un have become on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo by SAUL LOEB / AFP)        (Photo credit should read SAUL LOEB/AFP/Getty Images)
SAUL LOEB/AFP/AFP/Getty Images
TOPSHOT - US President Donald Trump (R) poses with North Korea's leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. - Donald Trump and Kim Jong Un have become on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo by SAUL LOEB / AFP) (Photo credit should read SAUL LOEB/AFP/Getty Images)
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SINGAPORE - JUNE 12: In this handout photo, North Korean leader Kim Jong-un shakes hands with U.S. President Donald Trump during their historic U.S.-DPRK summit at the Capella Hotel on Sentosa island on June 12, 2018 in Singapore. U.S. President Trump and North Korean leader Kim Jong-un held the historic meeting between leaders of both countries on Tuesday morning in Singapore, carrying hopes to end decades of hostility and the threat of North Korea's nuclear program. (Photo by Kevin Lim/THE STRAITS TIMES/Handout/Getty Images)
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(CNN) —  

The US government on Wednesday moved to increase economic pressure on North Korea, adding new sanctions that target one individual and three shipping companies in Singapore, China and Russia for violating restrictions on trade with Pyongyang.

The Treasury Department announcement follows criticism from US officials that United Nations members needed to more strictly enforce sanctions against North Korea as part of the effort to get Pyongyang to denuclearize.

US Ambassador to the UN Nikki Haley directly called out Russia and China in July, when she and Secretary of State Mike Pompeo called on other countries to maintain economic pressure on Pyongyang to push the country to denuclearize.

The Treasury Department slapped sanctions on China’s Dalian Sun Moon Star International Logistics Trading Co. and Singapore-based affiliate SINSMS Pte. Ltd. for working together to facilitate illicit shipments to North Korea by using falsified shipping documents, such as exports of alcohol, tobacco and cigarette products.

The agency also sanctioned Russia’s port service agency, Profinet Pte Ltd, and the company’s director general, Vasili Aleksandrovich Kolchanov, a Russian national. The company has provided port services at least six times to DPRK-flagged vessels that have been previously sanctioned, according to the US government.

“Treasury will continue to implement existing sanctions on North Korea, and will take action to block and designate companies, ports, and vessels that facilitate illicit shipments and provide revenue streams to the DPRK,” Treasury Secretary Steven Mnuchin said in a statement.

Mnuchin said there would be consequences against those for violating sanctions until there is full, verified denuclearization of North Korea.

In July, Pompeo said that North Korea was smuggling petroleum products “into the country at a level that far exceeds the quotas established by the United Nations.” Pompeo, speaking to reporters at the UN with Haley at his side, added that “illegal ship-to-ship transfers are the most prominent means by which this is happening.”

“The United States reminds every UN member state of its responsibility to stop illegal ship-to-ship transfers, and we urge them to step up their enforcement efforts as well,” Pompeo said. When sanctions are not enforced strictly, “the prospects for the successful denuclearization are diminished.”

Haley called out Russia and China directly. She referred to a US attempt on July 19 to bring a complaint before the UN to discipline North Korea for its smuggling. China and Russia blocked the measure.

“We have photographs of proof of ship-to-ship transfers,” Haley said. Speaking of the US complaint, she added, “Now for China and Russia to block it, what are they telling us? Are they telling us that they want to continue supplying this oil? They claim they need more information. We don’t need any more information. The sanctions committee has what it needs. We all know it’s going forward.”