Russian officials announced that thousands of dead Caspian seals washed up on their shores.
The cause of death for the seals has not been determined.
There have been a handful of events in the past decade where Caspian seals have died en masse.
Thousands of Caspian seals have been found dead on the Russian coast of the Caspian Sea, officials announced on Sunday.
The Ministry of Natural Resources of the Republic of Dagestan wrote in a Telegram post that environmental specialists were still counting the number of dead seals but that the current count stood at 2,500.
Officials said many of the seals were discovered "between the mouths of the Sulak and Shurinka rivers" and in the Yuzbash Canal of Dagestan.
The ministry did not specify a reason as to why the seals had died, but said that laboratory tests would be conducted to determine a cause.
The seals may have died weeks ago, Zaur Gapizov, head of the Caspian Environmental Protection Center, told the Associated Press, adding that there was no evidence fishing net entrapment caused the deaths.
The Caspian Seals Conservation Agency has reported multiple occurrences of large numbers of dead Caspian seals washing up on the shores of Dagestan over the past decade, including as recently as May.
Caspian Seals, the only marine mammal found in the Caspian Sea, is listed as an endangered species by the International Union for Conservation of Nature.
Threats to the species include accidental drowning due to fishing nets, hunting, and loss of habitat.