Ukraine and NATO have agreed to order a Naval flotilla to attempt to enter the Sea of Azov AGAINST RUSSIAN REGULATIONS - and try to dock at Mariupol, Ukraine.
Russia has explicitly stated that the Sea of Azov is OFF-LIMITS to NATO vessels.
This decision may result in naval warfare in the Black Sea between Russia and NATO naval forces if Russia declines to allow those vessels through its Kerch strait.
For its part, Russia allows commercial vessels to transit the Kerch Strait in order to make pick ups and deliveries to Ukraine at the ports of Mariupol and elsewhere, provided they notify Russian Coast Guard in advance, citing the name and registry of the ship, the cargo it is carrying and where it is heading.
Ukraine finds these requirements insulting and, a little over two months ago, tried sending naval vessels through without the paperwork.
That resulted in a gun battle between the Ukraine vessels and the Russian Coast Guard. Russia won. The Ukraine vessels were impounded and towed to Kerch; their crews arrested and jailed for 60 days on charges of unauthorized entry into Russian territory.