The Ukrainian government’s website says calls at Evpatoria, Kerch, Sevastopol, Feodosia, Yalta and Sevastopol are to be barred after it publishes an official decree from the ministry of justice registered on 24 June.

The move is reportedly being made because Ukraine cannot guarantee safe operations, but Russia has told the IMO it will ensure safety in all ports.

The ban could see Ukrainian forces patrolling waters around Crimea and policing vessel approaches.