More worrying developments
Another disquieting development: Ukrainian President Petro Poroshenko has reportedly convened his war cabinet.
Some thoughts on that video
This tweet seems to show the moment the Ukrainian and Russian ships collided:
Here's the latest from our news desk:
The Ukrainian Navy says Russia has opened fire on some of its ships in the Black Sea off the coast of the Crimean Peninsula late on November 25, striking one vessel and wounding a crew member. (Reuters/AP)
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BREAKING: The Ukrainian Navy says its ships have been fired upon: