Tension between Russia and Ukraine has been building for months off the coast of Crimea.

Under a 2003 treaty between Moscow and Kiev, the Kerch Straight and the Sea of Azov are shared territorial waters.

But recently, Russia began inspecting all vessels sailing to or from Ukrainian ports in the area.

The use of force by Russia to seize Ukrainian vessels - with casualties - is a major escalation.

But you won’t hear Moscow taking the blame.

Under President Vladimir Putin, when Russia has used force before, its line of defence has always been: "We didn’t start it."

That goes for the Russia-Georgia war of 2008, and the appearance of "Little Green Men" (Russian special forces) in Crimea in 2014, which preceded Moscow's annexation of the peninsula.

So expect Moscow to pin the blame for what happened on Sunday - and for whatever happens next - on President Petro Poroshenko’s government.