A major oil spill occurred in the Black Sea near the Russian port city of Novorossiysk (South).
More than one hundred tonnes of black gold were reportedly spilled into the water, WWF said on Wednesday.
The leak took place last weekend at the Yuzhnaya Ozereyevka terminal, not far from Novorossiysk, during the loading of the Greek flagged tanker Minerva Symphony.
On Monday, the Caspian Pipeline Consortium (CPC), which transports oil from the Caspian Sea to Novorossiysk and controls this terminal, announced that about twelve cubic meters of oil had been spilled over an area of 200 meters squares.
"The situation has returned to normal" Sunday morning and does not threaten the local population or environment, also said the consortium, owned in particular by the Russian oil giant Rosneft, the American group Chevron and the Italian company Eni.
But the World Wide Fund for Nature (WWF) assured Wednesday that the leak was much larger and could seriously damage the environment.
According to the NGO, which has set up its own system for monitoring ecological disasters, the oil slick was spread on Sunday over an area of 94 square kilometers.
This means that "at least a hundred tonnes of oil and probably even more" were spilled in the Black Sea, WWF said in a statement on Facebook.
"Despite an operational deployment of rescuers, oil has spread over a colossal area," he said, warning against "increased" risks of a negative impact on marine animals.
An investigation for environmental pollution
According to Alexei Knijnikov, an expert from the Russian branch of WWF, the oil stain was drifting north, already reaching the village of Abraou-Diourso known for its beaches and vineyards, and could reach the Utrish nature reserve.
The Russian Institute for Space Research at the Russian Academy of Sciences has also announced that it is monitoring this pollution, estimating - from satellite images to support it - that the oil stain was spread over about 80 square kilometers.
An investigation for environmental pollution has been opened, according to the Russian authorities.
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