MOSCOW (Reuters) - Russia’s FSB security services said on Monday that Ukrainian naval ships ignored warning shots, forcing Russian vessels to open fire for real, after they illegally entered Russian territorial waters.

The Ukrainian vessels were first to aim their guns at Russian vessels in the Kerch Strait, an FSB statement said.

Russia seized two small Ukrainian armored artillery vessels and a tug boat on Sunday. Kiev said its vessels did nothing wrong and has accused Russia of military aggression.