Two Russian tankers carrying oil products have been badly damaged and sunk in Black Sea, threatening ecological disaster, Russian authorities said on Sunday.

The cargo ship Volgoneft-212 split in half and sank after being hit by a large wave east coast of Russian-annexed Crimea, 8km from the Kerch strait in the Black Sea. The tanker was carrying 4,300 tonnes of low-grade heavy fuel oil, known as mazut. At least one crew member was reportedly killed. Shortly after the sinking of Volgoneft-212, another cargo transporter, the Volgoneft-239, carrying 4 tonnes of fuel oil got into difficulty due to the storm and reportedly sank.

Russian authorities took measures to eliminate the oil spill in the area. A rescue mission, which included tugboats, helicopters, and over 50 personnel, successfully rescued 13 crew members from one tanker before being halted due to poor weather conditions. The 14 crew members remaining on the second tanker are reported to have all the essentials for immediate life support, but they are expected to remain stranded until the weather improves.

A working group headed by Deputy Prime Minister Vitaly Savelyev was set up upon President Vladimir Putin’s order.

The incident occurred in Strait of Kerch connecting Crimea to Russia. The Kerch Strait is an important pathway for the export of Russian grain, as well as for crude oil, fuel oil, and liquefied natural gas.