Mr Putin said to Jose Manuel Barroso, who then passed the Russian leader’s remarks on to European leaders at the Nato summit over the weekend, “If I want to, I can take Kiev in two weeks,” according to Italy’s La Republica newspaper.
Mr Barroso revealed Mr Putin’s threat after Ukrainian president Petro Poroshenko, who yesterday accused Russia of “direct and undisguised aggression”, had left the summit table.
As tension increases in the region, Nato has said they will form a 4,000 strong spearhead force to go into action in 48 hours in response to Russian aggression in Ukraine.
At a pre-summit news conference, Nato secretary general Anders Fogh Rasmussen said alliance officials have drafted a detailed plan that "responds to Russia's aggressive behaviour" but also equips Nato to respond to all security challenges, wherever they may arise.
Mr Ramussen said the forces would be equipped to “travel light, but strike hard”.
Nonetheless, Frederica Mogherini, the EU’s new heady of foreign policy, warned there was no military solution for what is now Europe’s biggest crisis in decades.
Mr Barroso claims Mr Putin first made the remarks in a telephone conversation held on 29 August, when Mr Barroso held the Russian president responsible for the military action of the separatists in Ukraine.
Allegedly, Mr Putin interrupted saying: “The issue is not this. If I want, I can take Kiev in two weeks”.