An Iranian-flagged container ship, Nora, has been detained by Danish authorities, according to the Danish Maritime Authority.

The vessel is currently anchored east of Albaek in the northernmost part of Jutland, The Caspian Post reports, citing TV2.

The Danish Maritime Authority said the ship was detained due to incorrect registration. It will remain held until Iranian authorities confirm that the container vessel is properly registered and certified.

TV2 reported that the ship was previously named Cerus before changing its name several months ago. US authorities suspect the vessel may be part of a so-called “shadow fleet” allegedly used to transport Iranian and Russian oil.