MOSCOW — The Ukrainian navy said Sunday that Russia’s coast guard opened fire on and seized three Ukrainian vessels and wounded two crew members in the Black Sea following a tense standoff off the coast of the Crimean Peninsula.

Ukraine’s navy said that two of its vessels were struck and that Russian coast guard crews boarded them and a tugboat and seized them. The Russian Federal Security Service, known as the FSB and which is in charge of the coast guard, said that it has evidence that Ukraine was responsible for the clashes.