Upwards of 300 animals are believed to be dead, according to a zookeeper, after the destruction of a dam caused a massive flood in the Ukrainian city of Kakhovka.

The Kakhovka hydroelectric power plant’s dam, which is in the Russian-occupied Kherson Region of southeastern Ukraine on the front lines of the 15-month-old war, suffered major damage on Tuesday, sending huge amounts of water flowing into the nearby area, prompting emergency evacuations and worries of ecological damage.

In the fallout of the incident, the Ukrainian government pointed the blame at Russia, calling it a “terrorist attack.” The Kremlin countered, accusing Ukraine of damaging the dam while downplaying the scale of the damage. Newsweek was unable to verify either accusation.

Officials at the Kakhovka Dibrova Zoo claimed on Tuesday that the facilities was heavily impacted by the flooding. While unconfirmed, zoo owner Olena Navrotska told Ukrainian news outlet UP.Zhyttia that they believe all of the animals, about 300 in all, are dead, despite efforts to rescue them. Other reports said only ducks and swans survived.

“All the animals have stayed in the park since the first day of the invasion,” Navrotska said. “The animals were stuck in the park; the whole park was mined, covered with trees, and dug through with trenches. Evacuation was impossible. We were trying with all our might to keep the animals safe.

“How much effort was put in, how many people helped to save the animals in such terrible conditions, practically risking their own lives? And now Dibrova is gone—300 innocent animals, our beloved pets, are dead. Anfisochka, Charlik, Malysh the pony, Osia the donkey, Misha the raccoon, and all [the others]…”

Newsweek reached out to Ukrainian officials via email for comment.

Prior to the flooding, the zoo had been home to monkeys, raccoons, donkeys, ponies, nutrias, various birds, porcupines, marmots and turtles, among other species. The zoo had been under Russian occupation since the start of the invasion on February 24, 2022, with shelling taking place around the area, roadblocks being erected, and zoo workers being interrogated. As a result of that presence, the animals were essentially trapped on the zoo’s premises when the flooding began.

Ukrainian President Volodymyr Zelensky said in a statement that destroying the dam from the outside would have been “impossible” and that Russian forces had committed the act from the inside with mines.

“It is physically impossible to blow it up somehow from the outside, by shelling,” Zelensky said. “It was mined by the Russian occupiers, and they blew it up.”

Zelensky advisers further claimed that the dam was destroyed in an effort to make an upcoming counteroffensive more difficult for Ukrainian forces.