Mystery surrounds the whereabouts of the world-famous 007 spy dolphins seized from Ukraine by Russia amid speculation they could be deployed against the West.

Naval sources in Crimea said the creatures had begun their first military exercises under commander-in-chief Vladimir Putin, a claim quickly denied by his Defence Ministry.

In a day of Cold War-style intrigue and subterfuge, Russian officials then cast doubt on the existence of a dolphin naval squad - three months after heralding their 'defection' from Ukraine following Moscow's annexation of Crimea.

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

Naval sources in Crimea said the creatures had begun their first military exercises under commander-in-chief Vladimir Putin, a claim quickly denied by his Defence Ministry

Some news sources quickly insisted the Russian Black Sea fleet was not involved in any military use of dolphins, leading to uncertainty over their whereabouts and role

Confusion about the dolphins surfaced after a report by a state owned news agency Sputnik claimed Russia's Black Sea Fleet Special Forces had initiated its first exercises with the combat dolphins since they were taken from Ukraine.

A military source said: 'Training exercises were held in the Sevastopol Oceanarium in the search of military equipment at a depth of over 60 metres. An object that looked like a mine was spotted by a dolphin and tagged with a buoy.

'We had to practically start from scratch to teach the [mammals] to search for objects under the water because the Ukrainian Navy hardly worked with them.'

But other news sources quickly insisted the Russian Black Sea fleet was not involved in any military use of dolphins, leading to uncertainty over their whereabouts and role.

In March, Russian media reported that the dolphins had 'defected' to Moscow - along with many Ukrainian forces in Crimea - but now Russia has cast doubt on whether the squad even exists

Swimming: It's thought that Moscow has taken charge of 13 elite units of dolphins, and a number of military sea lions

Major General Igor Konashenkov, the Defence Ministry's official spokesman, said: 'There have been, and there are, no training exercises with dolphins.

'The bases of the Black Sea Fleet are safely protected by special technical means of anti-sabotage forces, that's why there is no need in using exotic ways of safeguarding adjacent waters.'

The office of the commander of the Russian Navy said dolphins had been used during the Soviet era, but this work had stopped and the animals had been sold off.

A source said: 'All services that were involved in the military training of dolphins in the Black Sea fleet under the Soviets were abolished after the collapse of the Soviet Union, almost quarter a century ago.

'No decisions on their restoration was made after Crimea's unification to Russia.

'Everyone who has been to a dolphinarium at least once knows that dolphins and seals can be trained to do anything. The question is if the military need that.'

One observer said: 'Perhaps the dolphins are KGB not military agents. Maybe they are now on a special mission which is why they deny their existence.'

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

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

The Russian military dolphin training programme dates back to Cold War era of the 1970s when the Soviet Union utilised the animals in Sevastopol to search for mines or spy on foreign ships.

After the fall of the USSR, they were passed to the Ukrainian Navy but when Russia annexed Crimea in March, the animals were reported to have returned to the control of Moscow.

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

The unit included 13 elite dolphins as well as a number of sea lions, it was claimed.

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.

NATO is now running constant patrols in the Black Sea due to the Ukrainian crisis, leading to speculation Russia could deploy them against Western ships.

Shortly after the annexe of Crimea, Moscow acknowledged that the bottlenose dolphins had 'defected' to Russia along with many Ukrainian forces.

The Sevastopol facility is said to be one of only two such combat dolphin training centres in the world. The other is run by the US Navy in San Diego, which also pioneered their use for military purposes.