Russia has formally acknowledged that it has conscripted Ukraine's 'spy dolphins' which means they could now be used in underwater naval operations against the West.

The specially trained mammals were seized when Russia annexed Crimea in March, and now Moscow has officially ruled out handing them back.

The combat dolphins are trained for military duties at the Crimean State Oceanarium, which was inherited by Ukraine when the Soviet Union collapsed 23 years ago.

Acting Sevastopol governor governor Sergei Menyailo said: 'The jurisdiction over this facility has been fully transferred to the Russian Defence Ministry.'

Scroll down for video

Unlikely threat: A Russian military dolphin is photographed carrying an underwater bomb. The specially trained animals came under Moscow's control when Russian siezed Crimea from Ukraine in March

Highly trained: The combat dolphins are prepared for military duties at the Crimean State Oceanarium, which was inherited by Ukraine when the Soviet Union collapsed 23 years ago

In March, Russian media reported that the dolphins had 'defected' to Moscow - along with many Ukrainian forces in Crimea. Today, however, was the first confirmation that Putin is now the mammals' chief commander

Moscow has taken charge of 13 elite unit of dolphins and a number of sea lions.

The creatures are trained to hunt for mines, plant bombs on hostile ships or attack enemy divers with special knives or pistols fixed to their heads.

Others were schooled for anti-sabotage and rescue missions.

The use of bottlenose dolphins as naval assets was begun during the Cold War in Sevastopol by the Soviet Union in 1973.

NATO is now running constant patrols in the Black Sea due to the Ukrainian crisis, which means in theory that Russia could deploy them against Western ships.

Display: The military dolphins are trained to hunt for mines, plant bombs on hostile ships or attack enemy divers with special knives or pistols fixed to their heads. Pictured is a fully kitted-out model of a military dolphin

Swimming: Moscow has taken charge of 13 elite units of dolphins, and a number of military sea lions

ROUBLE HITS NEW ALL TIME LOW AGAINST THE DOLLAR AS U.S. AND EU SANCTIONS TAKE THEIR TOLL Russia's rouble hit a new low against the dollar today. The currency has been hit by falling oil prices and a decision by the central bank not to raise interest rates despite investor concern over the economic effect of the Ukraine crisis. Russian assets took a beating last week after the United States and European Union imposed new sanctions over Moscow's role in the separatist conflict in Ukraine. The action further limits access to foreign capital for some of Russia's top companies. The rouble fell to a new all-time low of 38.00 roubles to the dollar in the first hour of trading today. By 09:00 GMT the rouble had extended losses to trade 0.81 per cent weaker against the dollar at 38.09, and 0.55 per cent lower at 49.21 versus the euro. Russia relies on oil and gas for about two-thirds of exports and half of federal budget revenues. Experts are predicting the rouble could fall still further over the coming week. These estimates are based on the fact rates for Russian companies looking to park foreign currency holdings at the central bank remain low, reflecting a weak demand. Advertisement

Four other dolphins used in Sevastopol in helping to treat children suffering from cerebral palsy, mental disorders and psychological stress have been moved to civilian duties by the Russians and will continue this valuable work.

In March, the Russian media reported that the dolphins had 'defected' to Moscow - along with many Ukrainian forces in Crimea - but this is the first official confirmation that the mammals' commander in chief is now Vladimir Putin.

In July a Ukrainian official demanded that the dolphins should be handed back to Ukraine.

'The military dolphins need to be returned to our country in the same way that Russia returned Ukraine's seized military equipment,' he said.

Last year three of five spy dolphins went absent without leave in the Black Sea - apparently in search of love.

'They deserted a naval exercise and went on manoeuvres of an amorous kind,' said a source. 'They swam away to look for mates.'

Later they returned to duties.Yury Plyachenko, a former Soviet naval anti-sabotage officer, explained that this was something that had to be taken into account in working with the 007 mammals.

'If a male dolphin saw a female dolphin during the mating season, then he would immediately set off after her. But they come back in a week or so.'

The Sevastopol facility is one of only two such combat dolphin training centres in the world. The other is run by the US Navy in San Diego.

Attack: NATO is now running constant patrols in the Black Sea due to the Ukrainian crisis, which means in theory that Russia could deploy the military dolphins against Western ships