The Ukrainian military has reportedly lost three dolphins which had been trained for military attacks in the Black Sea, Russia's state news agency RIA Novosti reports.

Ukraine's Defense Ministry press office has denied the reports and refused to comment on whether their navy trains dolphins to kill. They said the information in the media reports "does not agree with reality."

However, several local Ukrainian news outlets are reporting that former naval officers said dolphins often went missing on March 11 from the Sevastopol Aquarium during training exercises to find mates

The dolphins may have swum off to mate with wild dolphins, former soviet naval officer Yury Plyachenko told RIA Novosti. He said the dolphins have done this before and usually return to the base within a week.

"If a male dolphin saw a female during the mating season, then he would immediately set off after her," Plyachenko said.

The dolphins are trained to find underwater mines (which have been done in other military programs including Russia and the U.S.) but in the Ukraine, they are supposedly also trained to kill enemy divers with knives and pistols attached to their heads, according to RIA Novosti. Some could also be trained to place explosive devices on enemy ships.

One of the "killer" dolphins that have gone missing was reportedly armed at the time, according to a report