Putin warns Poland and Romania could be caught in the 'crosshairs' of Russian rockets for hosting a US defence shield that he considers a threat to national security

Vladimir Putin has warned that Romania and Poland could be caught in the 'crosshairs' of Russian rockets for hosting elements of a U.S. missile shield that Moscow considers a threat to its security.

The Russian president said Moscow would be 'forced to carry out certain measures' against the European nations, at an Athens conference on Friday.

Earlier this month the U.S. military - which says the shield is needed to protect from Iran, not threaten Russia - angered Russia by switching on the Romanian part of the shield. 

Vladimir Putin has warned that Romania and Poland could be in the 'crosshairs' of Russian rockets because they are hosting elements of a U.S. missile shield that Moscow considers a threat to its securit

Work is also going ahead on another part of the shield, in Poland.

'If yesterday in those areas of Romania people simply did not know what it means to be in the cross-hairs, then today we will be forced to carry out certain measures to ensure our security,' Putin told a joint news conference in Athens with Greek Prime Minister Alexis Tsipras.

'It will be the same case with Poland,' he said.

Putin did not specify what actions Russia would take, but he insisted that it was not making the first step, only responding to moves by Washington. 

'We won't take any action until we see rockets in areas that neighbour us.'

He said the argument that the project was needed to defend against Iran made no sense because an international deal had been reached to curb Tehran's nuclear programme. The missiles that will form the shield can easily reach Russian cities, he said.

'How can that not create a threat for us?' Putin asked.

He voiced frustration that Russia's complaints about the missile shield had not been heeded.

'We've been repeating like a mantra that we will be forced to respond... Nobody wants to hear us. Nobody wants to conduct negotiations with us.' 

The Russian president said Moscow had stated repeatedly that it would have to retaliate to the missile shield and would be 'forced to carry out certain measures' against the European nations, at an Athens conference on Friday

Speaking at a joint news conference in Athens with Greek Prime Minister Alexis Tsipras (right) on Friday, Putin did not specify what actions Russia would take, but he insisted that it was not making the first step, only responding to moves by Washington

Putin also sounded a defiant note over Crimea, the Ukrainian region which Russia annexed in 2014. Moscow said it was acting on the will of the Crimean people, who voted to join Russia, but Western governments say it was an illegal land grab.

'As far as Crimea is concerned, we consider this question is closed forever,' Putin said. 'Russia will not conduct any discussions with anyone on this subject.'

The Russian leader also touched on relations with Turkey, which have been toxic since the Turkish military shot down a Russian fighter jet near the Syrian-Turkish border last November. Ankara said the plane strayed into Turkish airspace, an allegation Moscow denies.

Putin said he was ready to consider restoring relations with Ankara, but that would require a first step from Turkey, and so far there was no sign of that.

Putin was asked about the South Stream project, a planned gas pipeline from Russia that would have gone under the Black Sea to Bulgaria and onwards to southern Europe. Russia shelved the project after Bulgaria backed out.

He blamed the U.S. government and the European Commission, saying they had pressured Sofia to withdraw. But he said Russia was going ahead with an extension of its Nordstream pipeline in the Baltic, and he hoped no one would try to hinder that project. 

He said the argument that the U.S. missile project was needed to defend against Iran made no sense because an international deal had been reached to curb Tehran's nuclear programme

On Saturday, Putin will visit the autonomous Orthodox Christian monastic community of Mount Athos, joined by the head of Russia's Orthodox Church, Patriarch Kirill of Moscow

Athens is keen to maintain its traditionally close ties with post-Soviet Russia, despite its participation in EU sanctions against Moscow, and a gas pipeline project designed to limit Russia's regional energy dominance.

Russia is one of Greece's main trading partners, but business has been hit by the sanctions and a drop in commodity prices.

Greece is also keen to reverse a slump in tourist arrivals from Russia last year, and attract interest from Russian companies in the planned privatization of rail and other transport services.

Putin's latest warning comes as Russia successfully tested an anti-satellite missile capable of wiping out U.S. navigation, communications and intelligence devices

Alexis Tsipras, the Greek prime minister, noted that Putin's visit comes just days after Athens reached a deal with eurozone bailout creditors to continue rescue loans, under a deal that expands power of a state privatization committee.

'Improving relations with Russia on multiple levels is a strategic choice,' Tsipras said. 'Of course ... when the disagreements exceed our powers, we can act a positive influence within the EU and NATO.' 

Putin's latest warning comes as Russia successfully tested an anti-satellite missile capable of wiping out U.S. navigation, communications and intelligence devices.

The Nudol direct ascent missile was launched from a facility in Plesetsk, 500 miles north of Moscow, and was monitored by U.S. intelligence.

It is unknown whether the Nudol was fired at a target or just launched on a suborbital trajectory but the successful test represents a major milestone for Russia as it continues to modernise its strategic arsenal under President Vladimir Putin.

The developments have been shrouded in secrecy but Russian state reports have insisted that the Nudol is for defence purposes, describing it as 'a new Russian long-range missile defence'.