Fresh oil started pouring from a stricken Russian tanker in the Black Sea on Friday, said officials in Moscow, as Ukraine warned of "terrible environmental consequences" from the spill.

Emergency workers toiling to clean up an oil spill in the Black Sea have detected seven new slicks, a Russian official told the TASS state news agency on Friday, as authorities struggle to mitigate the effects of the nearly month-old disaster.

In response to the scale of the disaster, thousands of workers from Russia's Ministry of Emergency Situations, along with numerous volunteers, have been deployed to clean up the beaches in the Krasnodar region.

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.

The Black Sea is home to different cetacean species — some endangered — and it was the site of an oil spill in the middle of December that killed 31 of them.

Russian President Vladimir Putin said on Thursday that more needed to be done to clean up an oil spill in the Black Sea, saying efforts so far appeared to have been insufficient to deal with the ecological disaster.

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

The Black Sea has recently faced a devastating environmental disaster due to an oil spill from Russian tankers. Russian President Vladimir Putin acknowledged the situation and stated that current efforts to address the crisis are insufficient,