MOSCOW, March 27 (RIA Novosti) - The Kerch Strait between the Black Sea and Sea of Azov is facing a new environmental disaster following a November fuel oil spill, Greenpeace said on Thursday.

A storm in the Kerch Strait sank four ships and an oil tanker on November 11. The incident resulted in about 2,000 metric tons of fuel oil spilling into the sea.

"Almost 1,500 metric tons of fuel oil landed on the bottom of the strait after the catastrophe. This spring the waves have lifted the fuel to the surface, and it is coming to the shore together with algae," said Alexei Kiselyov, coordinator of the environmental group's toxic substances division.

So far, an estimated seven kilometers (4.3 miles) of coast line has been polluted, Kiselyov said. He also said that the latest disaster could affect the 2008 holiday season and cause a decrease in revenue from tourism.

Russian authorities are carrying out a clean up operation at the tourist areas along the coast.

Experts earlier said petrochemical concentrations in the Kerch Strait following the storm were 50 times higher than maximum permissible levels. Some 50,000 birds have so far died as a result of the oil slick. The fuel penetrates birds' plumage causing hypothermia, and is ingested, usually with fatal results.

Ukraine plans to charge Russian ship-owners over $1 billion for the damage caused by the fuel oil spill in the Kerch Strait.