Speaking at a news conference at the Kremlin on Tuesday, Mr Putin said he had advised Ukraine not to join NATO, but admitted he would be unable to interfere in any such move.
"I am not only terrified to utter this, it is scary even to think that Russia, in response to a possible deployment of... [parts of the] missile shield in Ukraine... would have to target its offensive rocket systems at Ukraine," he said.
In a televised speech to the Russian State Council last week, Mr Putin had warned that a "new phase in the arms race is unfolding in the world".
He said other countries were spending far more than Russia on new weapons, but that it would respond to the challenges of an arms race by developing hi-tech weaponry.
One of the explanations commonly given for the fall of the old Soviet Union is that Western leaders cleverly pushed them into an arms race that they couldn't afford, eventually bankrupting the Communist block with bloated military budgets that caused all other sectors of their economy to suffer. There are some problems with that narrative. The most important flaw being the implication that the Western leaders had the slightest idea what they were doing. The next biggest flaw being the idea that such a policy, if intentionally pursued, would be anything except an extremely dangerous and unlikely gamble. Empires with bloated militaries, who feel their influence and position slipping are more likely to risk everything in one big gamble than to quietly accept the inevitable. The only reason we got out of the Cold War in one piece is because the Soviet Union was run by Mikhail Gorbachev and not Kaiser Wilhelm II. In history, Wilhelms are far more common than Gorbachevs.
When I say we made it out of the Cold War in one piece, I mean "we" in the most parochial sense--Americans and Western Europeans like me. People in Africa, Southeast Asia, and Central America did not get out of the Cold War unscathed. They had the unenviable role of fighting and dying in proxy wars so the self-proclaimed superpowers wouldn't fight each other directly.
Today, the United States spends more on its military than the entire rest of the world combined. Our current president, the party that supports him, and a large faction of the opposition party all believe that we must continue our military expansion and they are willing to sacrifice anything in the pursuit of that goal, including social services and economic infrastructure. Now our former opponent says he is willing to engage us in an arms race...