Vitaly Ilchenko, head of an ecopark near the second-largest Ukrainian city of Kharkiv, said part of the park was occupied by Russian military forces and that three employees were killed while trying to deliver food to the animals.
He also said that they decided to release deer, elk, red wolves and some birds in order to enable them to survive in the wild.
But Ilchenko says he fears lions and tigers from the ecopark, including his star attraction, the lion Simba, could starve to death.
And the staff of the zoo in the center of Kharkiv is making every effort to keep the animals whole and to keep them warm in their homes.
“Our monkeys need fruits and vegetables, and our predators need meat, and so do other animals,” Karina Detiuk, deputy director of the zoo, told the BBC.
“We do the impossible by trying to keep them all alive. Our wolves howl worse than air raid sirens and it breaks our hearts.”
Natalia Popova, who runs a wildlife shelter not far from Kiev’s main international airport, said the animals were under so much stress from the noise of Russian shelling that many began to injure themselves in their cages.
“One lioness injured her paw and can no longer stand on it, and a young deer crashed into a wall and died in the process because she fatally injured her neck,” she said.