Gen. Nikolai Solovtsov, head of Russia's strategic missile forces, said Monday that Russia might train its missiles on the two countries if they accept a U.S. proposal to base 10 interceptor missiles in Poland and a radar in the Czech Republic.
"I think that was an extremely unfortunate comment," Rice said at a news conference in Berlin, adding that the system did not threaten Moscow's forces "and we have had the opportunity to explain that to Russia."
She said the United States has made clear to Russia that the system would be to counter any missile threat from Iran. The system is too small to stop Russia's large nuclear arsenal, she said.
"Anyone who knows anything about this knows that there is no way that 10 interceptors ... are a threat to Russia or that they are somehow going to diminish Russia's deterrent of thousands of warheads," Rice said.
"I think everyone understands that with a growing Iranian missile threat, which is quite pronounced, that there need to be ways to deal with that problem," she added.
The missile dispute is chilling relations between Moscow and Washington, which have already been damaged by differences over NATO's eastward expansion and U.S. concerns over human rights in Russia.
Russian Foreign Minister Sergey Lavrov said Moscow sees the establishment of the missile defense sites as a signal that the United States wants to gain nuclear superiority over Russia. He dismissed U.S. claims that it was to counter Iranian threats.
"If they talk about potential threats coming from Iran or North Korea, missile defense elements should be located in a different place," Lavrov said in an interview published Wednesday in the daily Rossiyskaya Gazeta. "We can't help noting that these facilities would be capable of intercepting missiles launched from Russia."