Marine biologists moved a pair beluga whales, which were being shelled by Russian forces daily in the Ukrainian city Kharkiv, to Valencia in eastern Spain. They described the rescue as a risky and long international operation.

The animals, a 15-year old male Plombir, and a 14-year-old girl Miranda, arrived late Monday at Valencia's Oceanografic complex in a fragile health state, according to an announcement by the Spanish Oceanarium.

The belugas had to endure a long journey in fragile wooden boxes that began with a 12-hour drive from Kharkiv, Ukraine, to Odesa. The belugas were met by their Ukrainian keepers, as well as veterinarians from Georgia Aquarium and SeaWorld.

They then continued their journey to the Moldovan border, which was crossed with the help of the European Union Anti-Fraud Office. After a quick check-up, they continued their journey to the border with Moldova. They crossed it with the help of the European Union's Anti-Fraud Office.

Carlos Mazon said that the operation was a "historic feat in animal protection at a global scale".

Daniel Garcia-Parraga said the whales were "not in a condition to make this journey. But if they continued onwards, their chances of surviving would have been slim".

The NEMO Dolphinarium in Kharkiv was only 800 metres away from a frequent shelling site. Shockwaves were a major stress factor for animals that have such sensitive hearing.

Garcia-Parraga stated on Wednesday that the belugas are in better condition than what vets initially thought and have adapted well to their new environment.

Miranda, on the other hand, had not yet tried her first bite. Plombir had already eaten - which is rare for that species to do so immediately after transport.

Oceanografic is Europe's largest aquarium and only place to see beluga whales.

White-hued mammal species live in cold waters of the Arctic and subarctic regions. The males can grow up to 5 metres long and weigh up 1.6 tons. (Reporting and editing by David Latona, Catherine Macdonald)