Danish authorities have banned 27 Russian-linked ships from calling at local ports or anchorages.
Guidelines issued to Danish pilots, seen by Danish media outlets Danwatch and Information, also state that it is forbidden to provide services to the Russian ships, including bunkering and the sale of supplies.
The ban was introduced after the European Union introduced its 14th sanctions package against Russia this summer, which included the 27 Russian ships.
Pilots have been advised that the ships in the shadow fleet can change their names and that they must therefore check the ships’ IMO numbers.
The ships in the shadow fleet routinely stop at the anchorage outside Skagen, where they take supplies and provisions onboard and bunker oil before sailing on.
The Danish government has been in discussions with neighbours for months looking at ways of barring Russia’s shadow fleet from transiting the Baltic Sea, something that gained added importance following a collision involving a laden Russian shadow tanker earlier this year.
Russia sends about a third of its seaborne oil exports through the Danish straits with around one in three of these ships having unknown insurance.