Two tankers from Russia’s "shadow fleet" on fire in Black Sea off Turkish coast

Fires broke out in the Black Sea on two oil tankers that are part of Russia’s shadow fleet and are under Western sanctions. Turkey has said that the incidents on the Kairos and Virat tankers were the result of "external action".
Censor.NET reports this with reference to Radio Liberty.
Signs of external impact recorded on the tankers, crews are safe
The Turkish authorities reported fires on two oil tankers in the Black Sea following "external action".
Kairos and Virat are part of the shadow fleet
Both vessels are under Western sanctions as part of Russia’s so-called shadow fleet used to trade its oil.
Turkey’s Ministry of Transport released the following information:
It is reported that the empty tanker KAIROS, which was en route to the port of Novorossiysk (Russia), caught fire due to external impact 28 miles off the Turkish coast. All 25 crew members on board are in good condition. The ministry said its rescue units were dispatched to evacuate the sailors and that the situation is under control.
The tanker VIRAT reported that it had been hit roughly 35 nautical miles off the coast in the Black Sea. Rescue teams and a commercial vessel were sent to the scene. All 20 crew members on board are in good condition, while heavy smoke was detected in the engine room. The situation is reported to be under control.
Russian military bloggers claim that the VIRAT was attacked by five naval drones.