No evidence given. This is a recurring pro-Kremlin disinformation narrative about the Azov Sea incident. For earlier examples see here.
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.
The construction of the Kerch Bridge took place without Ukraine's consent and constitutes a violation of Ukraine's sovereignty and territorial integrity. It has led, in parallel with the militarisation of the Azov Sea, to tougher controls on naval traffic in the strait. The European Union stated
that it expects Russia to stop the inspections.