Moscow declined to deny that Putin had spoken of taking Kiev in a phone conversation on Friday with José Manuel Barroso, the outgoing president of the European commission, the Guardian reported Tuesday.
Yuri Ushakov, a Kremlin foreign policy adviser, on Tuesday said the Barroso leak had taken Putin's remarks out of context.
"This is incorrect, and is outside all the normal framework of diplomatic practice, if he did say it. This is simply not appropriate for a serious political figure," he said of the Barroso leak, according to the Russian Interfax news agency.
EU leaders held a summit on Saturday to decide who should run the union for the next five years. The session, however, was quickly preoccupied by Putin's invasion of Ukraine and how to respond.
EU leaders held a summit on Saturday and discussed about Ukraine
Barroso told the closed meeting that Putin had told him Kiev would be an easy conquest for Russia, according to La Repubblica, the Italian newspaper.
According to the account, Barroso asked Putin about the presence of Russian troops in eastern Ukraine. NATO says there are at least 1,000 Russian forces on the wrong side of the border. The Ukrainians put the figure at 1,600.
"The problem is not this, but that if I want I'll take Kiev in two weeks," Putin said, according to La Repubblica.
Without denying Putin's remarks about Kiev, the Kremlin complained about the leak of the Barroso remarks.
Meanwhile, Petro Poroshenko, the Ukrainian president, also attended the EU summit and painted an apocalyptic picture of the conflict.
German chancellor Angela Merkel, the main mediator with Putin, was said to be furious with the Russian leader, warning that he was "irrational and unpredictable", while British Prime Minister David Cameron was said to have raised the issue of Britain discussing policy options regarding Putin.