MOSCOW (Reuters) - The United States has imposed sanctions on a vessel that Reuters revealed last year was delivering oil products from Russia to North Korea.

The vessel, the Kum Un San, was one of eight vessels which Reuters found had left Russia with cargoes of fuel headed for North Korea despite declaring other destinations. U.S. officials say that is a ploy often used to skirt sanctions.

The North Korean-flagged Kum Un San, as well as the company that owned it, Korea Kumunsan Shipping Co, were among six vessels, nine entities and sixteen individuals sanctioned on Wednesday by the U.S. Treasury Department.

“Treasury continues to systematically target individuals and entities financing the Kim (Jong-un) regime (in North Korea) and its weapons programs, including officials complicit in North Korean sanctions evasion schemes,” U.S. Treasury Secretary Steven T. Mnuchin was quoted as saying in a statement announcing the new measures.

“We are sanctioning additional oil, shipping, and trading companies that continue to provide a lifeline to North Korea to fuel this regime’s nuclear ambitions and destabilizing activities.”

North Korea, which has no oil reserves, needs to import fuel to keep its struggling economy functioning. The United Nations tightened sanctions against Pyongyang on Sept. 11 last year, reducing the amount of fuel that can be sold to it. That has led to added scrutiny on oil supplies to North Korea, especially from neighboring countries.

According to the Russian Information System for State Port Control, the Kum Un San put into the Vostochny port on Russia’s Pacific coast on March 18, 2017 and loaded up with 2,100 tonnes of oil products.

It left Vostochny on March 23 and, according to port documents, gave the port of Dalian in China as its next destination. But Reuters ship-tracking data soon detected the vessel near the North Korean port of Chongjin.

After this journey it made only one port call in Russia on May 25, to the port of Vladivostok where it took on fuel for its own use but did not load or unload any cargo, according to the Russian Information System for State Port Control.

The Kum Un San’s transponder has been turned off since the end of June, Reuters ship-tracking data shows, apart from a few brief periods. U.S officials say vessels often switch off transmitters to undermine sanctions.

U.S. President Donald Trump said in an interview with Reuters last week that Russia was helping North Korea evade international sanctions and was probably helping supply Pyongyang with anything that China had stopped giving it. Moscow rejected allegations that it is in breach of U.N. sanctions on North Korea.