Escalations in Ukraine-Russia tensions are serious
For Russia to have opened fire on Ukrainian vessels is a new departure and a serious escalation, writes Sky's Diana Magnay.
Tuesday 27 November 2018 15:28, UK
There's always an element of "he said, she said" in each new iteration of Russian-Ukrainian tensions.
What to Ukraine is an unprovoked act of aggression is to Russia a response to a flagrant provocation.
Reality is murky and as is often the case in conflict, both sides would keep it that way.
Russian territorial waters around the Crimean peninsula depend on whose territory you think Crimea is. Only Russia believes it is theirs, which makes accusations of illegal entry even murkier.
The Sea of Azov and Kerch Strait are shared territorial waters thanks to a 2003 agreement, but this incident happened in the Black Sea.
Ukraine says they gave all the requisite requests and assurances; Russia says they didn't.
For Russia to have opened fire on Ukrainian vessels is a new departure and a serious escalation.
No more little green men or Russian "volunteers", Sunday's incident was one state against the other - Russian naval officers giving the order to shoot.
Kiev's decision to impose martial law across parts of Ukraine for an initial 30-day period may represent another escalation. It begs the question why Ukraine's president has done this now when he didn't during the height of the shooting war in 2014 and 2015.
Ukraine's east is tense anyway thanks to four-and-a-half years of simmering conflict; putting nine regions on more of a war footing will only make it more so.
President Petro Poroshenko says he has intelligence Russia is planning a land invasion.
That's been the concern since 2014, but Russia so far has not moved to create a land corridor between the Russian border and Mariupol and its operations in the east are still covert.
The conflict in eastern Ukraine is also already long and costly for Russia, so it is hard to see why it would wish to go in guns blazing now. But with tensions this high it is all too easy for them to spiral out of control.
What is clear is that Moscow is becoming more assertive around the Sea of Azov.
Despite sanctions against the companies involved in its construction, the Kerch Strait Bridge is built - nearly 12 miles of motorway which connects the Russian mainland with Crimea.
Each metre of asphalt is one more mark of dominance over the peninsula itself and the waters beneath.
The deployment of Russian naval assets to the Sea of Azov which picked up as the bridge neared completion is both a threat to Ukrainian economic activity coming in and out of the Strait and an implicit stake of ownership over those troubled waters.
Russia's sovereignty over Crimea is de facto if not de jure. Ukraine is right to be anxious that Russia does not appropriate those waters the same way.