Kyiv: A crew member’s urgent radio call came moments after the Russian oil tanker Virat was hit by an underwater unmanned drone in the Black Sea early Saturday, a day after the same vessel was struck by explosions, Ukrainian and Turkish officials said.

The Virat and another tanker, Kairo, had issued open-frequency distress calls reporting a “drone attack,” referring to unmanned maritime drones targeting them, according to recordings from the scene.

In a video recording of the call, a crew member can be heard saying, "This is VIRAT. Help needed! Drone attack! Mayday!"

Late Friday, both ships were rocked by blasts off Turkey’s coast, Turkey’s transport ministry said. One of them was hit early Saturday again, the ministry added.

Ukraine has claimed responsibility for the strikes. Russia’s so-called shadow fleet was targeted in the attack, CNN reported, citing an official with Ukraine’s Security Service, or SBU.

A source in the SBU told AFP that “modernised Sea Baby naval drones successfully targeted the vessels.” The source also released a video that appeared to show sea drones moving toward the ships before explosions erupted.

The official said the two tankers are under Western sanctions and that Ukrainian intelligence is continuing “to take active steps to curtail Russia’s financial capabilities to wage war against Ukraine.”

The SBU said the Sea Baby drones disabled vessels capable of transporting nearly $70 million worth of oil, disrupting Russia’s efforts to get around international sanctions.

Earlier, Turkish Transport and Infrastructure Minister Abdulkadir Uraloglu said the ships were possibly struck by mines, missiles, a marine vessel or a drone. The incidents occurred within Turkey’s exclusive economic zone, he said. Authorities were coordinating with counterparts “to prevent a recurrence and to ensure navigational safety,” he added.