MOSCOW, November 25. /TASS/. Russia’s Federal Security Service has blasted as provocation the intrusion of three Ukrainian vessels into Russia’s territorial waters.

"The provocation of three vessels of the Ukrainian Navy has been ongoing for the fifth hour in Russia’s territorial waters of the Black Sea. Their goal is clear - to create a conflict situation in this region," the FSB press service said.

The FSB Border Service is taking all steps to thwart this provocation by the Ukrainian leadership and ensure safe navigation, it said.

Earlier on Sunday, the Russian Federal Security Service’s Border Service in Crimea reported that three Ukrainian warships had illegally crossed Russia’s state border entering its territorial waters, and were carrying out dangerous maneuvers.

A source in law enforcement agencies of the South Federal District identified these vessels as two small armored boats Berdyansk, Nikopol and tugboat Krasnoperekopsk (which was renamed by Ukraine).

The Treaty on the Legal Status of the Sea of Azov and the Kerch Strait, signed in 2003, confirmed their status as domestic waters of Russia and Ukraine. The sides agreed on the joint usage and protection of the Sea of Azov and the Kerch Strait and introducing restrictions for vessels of third countries.