The Kerch Strait incident was merely a rehearsal for a larger provocation to drag Russia into war. Such attempts have been going on for five years. But it did not work. Ukraine expected that all 24 sailors would die, but only 3 were injured.
On November 25th 2018, border patrol boats belonging to Russia’s FSB security service seized two small Ukrainian armoured artillery vessels and their crews after shooting at them, wounding several Ukrainian servicemen. Russia argued that they were in Russian waters.
However, a bilateral treaty between Russia and Ukraine, signed in 2003 and ratified by Russia in 2004, governs the use of the Kerch Strait and the Sea of Azov, which in the treaty are considered to be the “internal waters” of both Russia and Ukraine.