A state of emergency has been declared in Russia after two oil tankers sank off the coast of Crimea, resulting in a massive oil spill into the sea.

The two vessels sank in the Kerch Strait, which connects the Black Sea and the Sea of Azov, on the morning of December 15.

The incident began when the craft Volgoneft-212, registered in the port of St. Petersburg, suffered a hull breach. Twelve crew members were rescued from the tanker, but one died from hypothermia.

An hour and a half later, in the same area, the tanker Volgoneft-239 also sank. Its stern drifted toward the shore and grounded. The crew was evacuated the next day.

The Russian Academy of Sciences estimates that about 3,000 tonnes of oil leaked into the sea.

The oil slick eventually started drifting towards the Russian coastline, prompting authorities in Anapa to declare a state of emergency on December 17.

More than 400 specialists and over 60 pieces of equipment have been sent to the town to handle the oil spill, the Russian Ministry of Defence said.

The operation is made difficult by strong winds, the Ministry added.

Footage shows Russian experts collecting samples of the spilled oil from the beach.

Another, apparently filmed by an outraged local, shows a bird stuck in thick oil that appears to be quickly overtaking the entire coast.

A specialist report has been ordered to determine the extent of the oil spill's environmental impact.

The Russian Minister of Natural Resources and Environment, Alexander Kozlov, said: 'It's too early to say exactly how much fuel oil has leaked into the sea; part of it remains in the tankers.

'Our primary task now is to identify, contain, and eliminate these oil slicks as much as possible. Additionally, the shoreline is being continuously monitored to prevent the slicks from reaching the coast.'

Kozlov said that they are doing everything they can to minimise the environmental impact, adding that the situation is currently under control.

Crimea's Investigative Committee has launched two criminal cases for non-compliance with transport safety requirements.