Kiev wants to make the Sea of Azov accessible to NATO forces and Ukraine could be responsible for the naval incident in the Straits of Kerch. Russia’s actions were entirely legitimate. According to the data of the Russian Federal Security Service (FSB), the Ukrainian ships had approached the Straits without any warning, had not waited for the Russian pilot and had not complied with the indications of the border guards, thus violating the legislation. The provocations may have continued throughout the day, leading the Russian side to open fire, injuring three Ukrainians and stopping the ships.
The article is a complication of evidence provided by the Russian security services FSB. The story has been published here also.
According to the research group Bellingcat, data, based on geolocated video footage, confirms that Ukrainian ships did enter Russian-claimed territorial waters (They are, in fact, only Russian-claimed territorial waters, rather than internationally recognised boundaries), both that of Crimea and mainland Russia in the Kerch Strait. Ukraine, nonetheless, argues this was legally permissible due to the 2003 agreement between the two countries. Secondly, we can say that the Ukrainian tug ‘Yani Kapu’ was intentionally rammed at least four times over a period of at least an hour. Thirdly, based on information provided by the Russian FSB which appears to incriminate themselves, the shooting of the ‘Berdyansk’ most likely took place in international waters.
For details on the incident: see Bellingcat.