Three dolphins trained by the Ukrainian Navy allegedly escaped on Tuesday into the Black Sea during a training exercise.

An expert source for the Russian news site RIA NOVOSTI claimed that the killer dolphins currently on the loose were a part of a group of five that were trained by the military to find sea mines.

The military program of training the dolphins for battle has repeatedly been denied by the Ukrainian Defense Ministry, according to Wired Magazine.

The aquatic mammals have reportedly been used before for military purposes in Russia since the 1970s, but the program was allegedly handed over to the Ukrainian Navy.

Former Soviet naval anti-sabotage officer Yury Plyachenko talked to RIA NOVOSTI about the attack dolphin program and potentially why the dolphins escaped.

"Control over dolphins was quite common in the 1980′s," Plyachenko explained. "If a male dolphin saw a female dolphin during the mating season, then he would immediately set off after her. But they came back in a week or so."

The thought that the dolphins are likely after mates is shared with other experts for explaining their disappearance, according to iScienceTimes.

The killer dolphins have apparently been trained for multiple uses that also include attacking divers and even to carry explosives on their heads to plant on enemy ships.

A military source in Sevastopol stated that the attack dolphins trained to attack enemies can carry special knives or pistols on their heads, according to Slash Gear.  

There is no evidence on whether the dolphins were equipped with weapons when they made their escape.

Ukraine is not the only country that is linked to using dolphins for military use.

The U.S. Navy uses dolphins to aid with undersea searches, but reportedly does no train them for attack purposes, according to ABC News.