The White House said plans to construct a missile defense shield in Eastern Europe remain on track despite a warning by President Dmitry Medvedev that the program could upend the "reset" between the two countries and lead to a new arms race.
"Its implementation is going well and we see no basis for threats to withdraw from it," White House National Security Council spokesman Tommy Vietor said late Wednesday.
Medvedev had said Russia would not only drop out of the New START nuclear arms reduction pact, but would target any installations built with its own ballistic missiles if a shield system is deployed.
The U.S. defense plan — in discussions since 2002 — calls for building interceptor missile sites and radar installations in Poland and Romania and possibly Bulgaria by 2020.
American officials have insisted that the plan is designed to defend against the growing missile threat from Iran and that Russia has nothing to worry about.
"The United States has been open and transparent with Russia on our plans," Vietor said. "We continue to believe that cooperation with Russia on missile defense can enhance the security of the United States, our allies in Europe and Russia."
Medvedev said Moscow has not been satisfied by America's assurances and that there needs to be a binding agreement.
"When we propose to put it on paper in the form of precise and clear legal obligations, we hear a strong refusal," Medvedev said.
Meanwhile, NATO Secretary-General Anders Fogh Rasmussen said he was "very disappointed" by Moscow's threat to deploy missiles, which he called "reminiscent of the past … and inconsistent with the strategic relations NATO and Russia have agreed they seek."
"Cooperation, not confrontation, is the way ahead," he said in a statement.