Kiev and Moscow have been embroiled in a naval standoff for the past two weeks. Three Ukrainian Navy vessels were seized on November 25 after violating Russia's maritime border.

Axar.az reports, Ukrainian boats had attempted a provocation in the Sea of Azov a month before the Kerch Strait incident, according to a senior Russian naval official.

Two Ukrainian armoured gunboats, the Lubna and the Kremenchug, escorted a vessel carrying a Bulgarian flag from the Ukrainian port of Mariupol through the Kerch Strait, Vice Admiral Aleksei Volsky, first deputy head of Russia's FSB coast guards, told a briefing in Moscow on Saturday.

He went on to say that during the operation, the Ukrainian vessels threatened to use force against Russian coastguard ships and set their weapons on standby.