Their legal right is disputable as previous agreement was explicitly linked to "Treaty of Friendship with Russia" that they terminated this September.
All ships also have legal duty to obey commands of relevant authorities, which they ignored.
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Reported by Ukrainian blogger Sharii (who
posted recording made by one of the ships around the area) - but i don't think listening to Ukrainian and Russian conversations is going to be particularly helpful on this board.
Obviously that isn't full recording as entire incident went on for 15 hours, but it does make quite solid impression...