The Reuters news agency reports that Russian tankers have supplied fuel to North Korea on at least three occasions in recent months by transferring cargoes at sea, providing an economic lifeline to the communist state.
According to one of two unnamed senior Western European sources speaking on condition of anonymity and quoted by the agency, the Russian vessels "made transfers at sea to the North Koreans."
The sale of oil or oil-products from Russia, the world's second biggest oil exporter and a veto-wielding member of the United Nations Security Council, breaches UN sanctions, Reuters quoted the security sources as saying.
A second source said there was no proof of Russian state involvement in the transfers.
"There is no evidence that this is backed by the Russian state but these Russian vessels are giving a lifeline to the North Koreans," the source said.
The Russian Foreign Ministry reacted to the report by saying that the country was observing sanctions against North Korea.
"Russia observes fully the sanctions regime," the ministry said in comments carried by the state-run TASS news agency.
"We would like to remind that fuel supplies, of course, have quotas, but no absolute ban," the ministry added.
The U.S. State Department called on Russia and other UN members to "strictly implement" sanctions on North Korea and to work "more closely together to shut down UN-prohibited activities, including ship-to-ship transfers of refined petroleum and the transport of coal from North Korea.”
With reporting by Reuters and TaSS