Thirty-two dolphins have died since fuel oil spilled from two storm-hit tankers three weeks ago in the Kerch Strait, which separates the Russian-occupied Crimean peninsula from Russia’s southern Krasnodar region, an animal rescue group said on Sunday.

Russia’s Delfa Dolphin Rescue and Research Center said the deaths were “most likely related to a fuel oil spill.”

The center said on the Telegram messaging app that a total of 61 dead whales – an order of aquatic mammals that includes whales and dolphins – have been recorded since the emergency, but the condition of the bodies suggests the other 29 died before the spill. .

“Judging by the condition of the bodies, most likely most of these whales died in the first 10 days after the disaster. And now the sea continues to wash them away,” the center wrote, noting that most of the dead dolphins were from the endangered Azov species.

Russia’s Emergencies Ministry said Sunday that officials and volunteers had removed more than 96,000 tons of contaminated sand and soil off the coast of Anapa and Temryuk districts in the Krasnodar region.

The ministry said it was working to clean up after the incident, but that “strong winds and waves” had washed the oil onto some beaches.

More than 68 kilometers of the coast have been cleaned, it is stated.

In a further statement on Sunday, the ministry said two new oil slicks had been discovered.

One was near the resort of Anapa, and the other was in Kapsel Bay, according to a statement cited by the Russian news agency TASS.

The news agency said the second blob was two kilometers long.

The type of fuel oil involved in the incident is particularly difficult to clean up because it is thick and heavy and does not float on the surface, Russian authorities say.

Russian-appointed officials in Moscow-occupied Crimea declared a regional state of emergency on Saturday after oil was discovered off the coast of Sevastopol, the peninsula’s largest city, some 250 kilometers (155 miles) from the Kerch Strait.

On December 23, the ministry estimated that up to 200,000 tons in total may have been contaminated with fuel oil, a low-quality heavy petroleum product.

Russian President Vladimir Putin called the oil spill an “ecological disaster.”

The Kerch Strait is an important global maritime route, which enables passage from the Sea of ​​Azov to the Black Sea.

It was also a key point of conflict between Russia and Ukraine after Moscow annexed the peninsula in 2014. In 2016, Ukraine sued Moscow at the Permanent Court of Arbitration, accusing Russia of trying to illegally take control of the area. In 2021, Russia closed the strait for several months.

Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelenskyi’s chief of staff, described last month’s oil spill as a “large-scale environmental disaster” and called for additional sanctions against Russian tankers.

Oil spills have affected marine life in recent years. Last year, an oil spill that leaked more than 34,000 gallons into the south Louisiana Bayou it killed at least 17 newts and three turtles, while three ducks and three alligators were reportedly covered in oil.

In 2022 a massive diesel gameI killed thousands of animals near New Orleans. The year before that, Louisiana wildlife officials said they documented more than 100 birds soaked in oil after crude oil spilled from a refinery flooded during Hurricane Ida.

At least in 2020 38 dead dolphins washed ashore on the island of Mauritius after a massive oil spill from a Japanese ship.

Agence France-Presse contributed to this report.