(CNN) Around 2,500 endangered seals have been found dead on Russia's Caspian coast, state-run news agency RIA Novosti reported Sunday, citing authorities in the North Caucasus region.
Caspian seals, the only mammals found in the Caspian Sea, have been classified as endangered on the International Union for Conservation of Nature (IUCN) red list since 2008.
The seals washed up on the coast of Russia's republic of Dagestan, along the Caspian Sea, the largest landlocked body of water in the world, which is bordered by five countries: Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan.
Dagestan's Ministry of Natural Resources said the animals had died of "natural factors" and warned that the number of dead seals was likely to be much higher.
Judging by their appearance, the seals died about two weeks ago and there were "no signs of violent death, no remains of fishing nets," the ministry said.
According to RIA, inspectors were patrolling the coastline in search of additional dead seals. Meanwhile, specialists from the Caspian Environmental Center were analyzing samples from the dead seals to identify the cause of death.
The mass deaths come after more than 140 Caspian seals were found dead on Kazakh beaches of the Caspian Sea earlier this year, according to KASPIKA, an agency for the conservation of Caspian seals.
According to the IUCN, the Caspian seal population has suffered from over-hunting, habitat degradation and climate change.
Following this incident, the Dagestan ministry said the overall number of Caspian seals in the area remains stable, "ranging from 270,000 to 300,000."
Feeding mainly on fish, the seals, which can reach a length of more than 1.6 meters (5.2 feet) and weigh up to 100 kilograms (220 pounds), are at the top of the food pyramid and have no natural enemies as adults, according to RIA.