Russia's Ministry of Foreign Affairs says it hopes Western countries will not take part in any Ukrainian attempt to stage what it has called "a provocation" near the Kerch Strait and dissuade Kiev from escalating tensions in the area.
Ukraine said last week it planned to send warships to its Azov Sea ports via the Kerch Strait despite Russia's seizure of three navy vessels and their crews in the area in November.
British defence minister Gavin Williamson visited Ukraine last week where he told his Ukrainian counterpart that the Black Sea did not belong to Russia and that Britain had sent a Royal Navy ship there to show Kiev did not stand alone.