MOSCOW (AP) — Russia and Ukraine traded accusations Wednesday over an incident involving a Ukrainian military aircraft flying over a Russian-operated gas rig in the Black Sea.

Ukrainian presidential spokesman Svyatoslav Tsegolko said the aircraft was fired upon while flying near two offshore gas rigs Wednesday. He posted a picture on Facebook showing a hole in the plane but added that the crew was not hurt.

Russia's Black Sea Fleet rejected the claim. It said the Ukrainian plane made two "provocatively" low runs over the Russian rigs, and a security officer fired a flare gun four times to drive it away and prevent a crash. It said in a statement carried by Russian news agencies that the flares posed no danger to the plane.

The Russian Defense Ministry later summoned Ukraine's military attache in Moscow to lodge a formal protest against what it called the plane's dangerous maneuvers.

The incident reflects the high tensions between the ex-Soviet neighbors following Moscow's annexation of Ukraine's Crimean Peninsula and support for a pro-Russia separatist insurgency in eastern Ukraine. It comes amid the worst fighting in months this week around Avdiivka, just north of the main rebel stronghold of Donetsk.

The rigs, which previously had belonged to Ukraine, have caused tensions for a long time. Ukraine has accused Russia of illegally seizing them and said it would demand compensation.