"This project is aimed against the strategic potential of Russia. And we can only give it an adequate response,`` Mr Putin said on Monday at a conference on human rights law in Saint Petersburg.
"If there are not missile defence sites in Poland and the Czech Republic - there will be no retaliatory measures either.``
Mr Obama, who takes office on January 20, has yet to give firm details over whether he intends to continue the plan which was created by the outgoing administration of Republican President George W Bush.
Mr Putin said that if the new Obama administration was prepared to drop the plan, then "by itself, the question of our retaliatory measures would be dropped.``
"Then we can break the dangerous, negative trend on the European continent,`` he said.
Earlier this month Moscow raised alarm in Western capitals by warning it could place missiles in the Russian enclave of Kaliningrad, close to Poland, in response to the plan.
