Russia declared a federal emergency on Thursday over an oil spill caused by two Russian tankers in the Black Sea, the Emergencies Ministry said.

Some 3,700 tons of low-grade fuel oil have spilled into the Black Sea since two Russian oil tankers were severely damaged in a storm on Dec. 15.

Crimean activists warn that the situation on the occupied peninsula could be even worse than on the Russian side of the Black Sea coast. According to one of them, the consequences of the oil spill on the Crimean beaches are more dangerous than in the Russian city of Anapa.

Russia launched aerial attacks on Ukraine’s energy sector “on a massive scale” overnight into Wednesday, local authorities said, with explosions reported across the country amid intensified bombardments that have left Ukraine in a precarious position while the war grinds into a third winter.

Russia attacked Ukraine's energy system and some cities with cruise and ballistic missiles plus drones, Ukraine's President Volodymyr Zelenskiy said.

Ukraine's air force says it detected 184 missiles and drones, causing damage to energy infrastructure across the country.