An animal rescue group said 61 dead cetaceans - an order of aquatic mammals that includes whales and dolphins - had been recorded since the oil spill.

Oil from two ageing and damaged Russian tankers was detected Friday off the coast of Sevastopol, the largest city in Moscow-annexed Crimea, a local official said.

A dolphin rescue center in Russia says 32 dolphins have died since fuel oil spilled out of two storm-stricken tankers three weeks ago in the Kerch Strait near the Russia-occupied Crimean Peninsula

In a heartbreaking scene, some 32 dolphins have washed up on a beach near Russia. The cause for this tragedy was down to a major oil spill with Russian President Vladimir Putin calling it an "ecological disaster".