Mr. Putin, in an interview at his country residence outside Moscow, said he considers U.S. plans to build an eastern European anti-missile site to shoot down Iranian missiles a provocation aimed at Russia.
Asked what he might do to retaliate, he said he would return Russia to the Cold War status where missiles were aimed at European targets.
"It is obvious that if part of the strategic nuclear potential of the United States is located in Europe, and according to our military experts will be threatening us, we will have to respond," he said.
"What kind of steps are we going to take in response? Of course, we are going to get new targets in Europe."
He suggested that this could include powerful nuclear-capable weapons.
"What kind of means will be used to hit the targets that our military believe are potential threats to the Russian federation? This is a purely technical issue, be it ballistic missiles or cruise missiles, or some kinds of novel weapons systems - this is a purely technical issue."