Vladimir Putin has warned that a new underwater missile system deployed by Russian submarines in the war against ISIS in Syria could be equipped with nuclear warheads.
The Russian president said that although using nuclear weapons was a possibility, he hoped that they would 'never be needed' in the fight against terrorism.
His warning came as Russia stepped up its barrage on Syrian rebels with its first submarine-launched cruise missile strikes combined with bombing raids from the air.
Russia has for the first time in the Syrian conflict used submarines (pictured) in the Mediterranean Sea to launch cruise missile strikes on rebels
Some of the missiles launched by the Russians are believed to be able to travel up to 1,500 miles as the country targets rebels as well as ISIS militants in the ongoing civil war
Speaking on Russian state television today, Putin claimed his military had struck '300 targets of different kinds' in the past three days and helped Syrian special forces recover the black box of a Russian warplane downed by Turkey last month.
President Putin said the cruise missiles, launched from the submarine in the Caspian Sea, could be equipped with nuclear warheads but said he hoped they would 'never be needed in the fight against terrorism'.
'With regard to strikes from a submarine: we certainly need to analyse everything that is happening on the battlefield, how the weapons work.
Both the [Kalibr] missiles and the Kh-101 rockets are generally showing very good results. We now see that these are new, modern and highly effective high-precision weapons that can be equipped either with conventional or special nuclear warheads.'
'Naturally, we do not need that in fighting terrorists, and I hope we will never need it. But overall, this speaks to our significant progress in terms of improving weaponry and equipment being supplied to the Russian army and navy.'
A Russian Tu-22M3 bomber drops bombs on a target in the latest round of air strikes in Syria
Moscow is flexing its military muscle with the latest submarine strikes after having previously fired missiles from warships in the Caspian Sea. Pictured are bombs being released in its latest air strikes
The country's Defence Minister Sergei Shoigu confirmed the strikes had been launched from the submarines, progressing on from firing from warships in the Caspian Sea.
'We used Calibre cruise missiles from the Rostov-on-Don submarine from the Mediterranean Sea,' Shoigu told President Vladimir Putin during an encounter broadcast on state television.
It is believed the cruise missiles, launched from submarines, can travel as far as 1,500 miles at low altitude to attack enemy strongholds.
Shoigu added that Russian strikes launched yesterday had been aimed at 'two terrorist strongholds' around Raqqa, the de facto Syrian capital of the Islamic State jihadist group.
'As a result of the successful launches by the aviation and submarine fleet, all targets were destroyed,' Shoigu said, adding that oil infrastructure, ammunition depots and a mine-making factory had been hit in the strikes.
'The Calibre cruise missile once again showed its effectiveness over long distances.'
Moscow is flexing its military muscle with the latest submarine strikes after having previously fired missiles from warships in the Caspian Sea.
Oil infrastructure, ammunition depots and a mine-making factory were hit in the latest Russian attacks
Russian strikes launched yesterday had been aimed at 'two terrorist strongholds' around Raqqa
This screenshot shows how the target is locked in and the missile lands during the targeted strikes
The Russian government has said the military would be continuing to conduct submarine strikes
Meanwhile it has emerged the number of foreign fighters joining ISIS and other extremist groups in Iraq and Syria has more than doubled since last year to at least 27,000, a report by an intelligence consultancy has revealed.
The figures, compiled by The Soufan Group, indicate that efforts by countries around the world to stem the flow of foreign fighters to the region and blunt the appeal of violent organisations appear to have made little impact.
'The foreign fighter phenomenon in Iraq and Syria is truly global,' the New York-based security consultancy's report said.
'The Islamic State has seen success beyond the dreams of other terrorist groups that now appear conventional and even old-fashioned, such as Al Qaeda.
'It has energised tens of thousands of people to join it, and inspired many more to support it.'
An unnamed source told Interfax news agency earlier that a Russian submarine was approaching Syria's Mediterranean coast to launch cruise missiles toward to war-torn country.
A Syrian teenager carries an injured boy following reported airstrikes on the town of Hamouria in the eastern Ghouta region, a rebel stronghold east of the Syrian capital Damascus
At least 11 civilians, including four children, were killed in airstrikes on Hamouria, but it has not been confirmed if they were carried out by Russian or regime aircraft
Relatives stand over an injured boy in a makeshift hospital following reported airstrikes on the town of Hamouria in the eastern Ghouta area
Moscow is flexing its military muscle with the latest submarine strikes after having previously fired missiles from warships in the Caspian Sea
Shoigu said Moscow had warned Israel and the United States - conducting their own bombing campaigns in Syria - that the Russian military would be conducting the submarine strikes.
Shoigu added that Russian military jets had conducted 600 combat sorties and destroyed '300 targets of different kinds' in the past three days.
Putin and Shoigu's televised statements came as Turkey's prime minister accused Russia on of carrying out 'ethnic cleansing' in northern Syria,
Ahmet Davutoglu accused Moscow was trying to drive out the local Turkmen - ethnic Turks living in Syria - and Sunni Muslim populations to protect its military interests in the region.
Davutoglu's comments could further harm strained relations between Moscow and Ankara, already at their worst in recent memory after Turkish forces downed a Russian warplane near the Turkish-Syrian border late last month.
'Russia is trying to make ethnic cleansing in northern Latakia to force (out) all Turkmen and Sunni population who do not have good relations with the regime,' Davutoglu told foreign reporters in Istanbul.
'They want to expel them, they want to ethnically cleanse this area so that the regime (of Syrian President Bashar al-Assad) and Russian bases in Latakia and Tartus are protected,' he said,