"This will be a strong action designed to weaken Russia's nuclear deterrent. We would have no other choice than to take measures of reprisal," spokesman Mikhail Kamynin said in a foreign ministry statement.

The warning comes a week after Russia's nuclear weapons chief reportedly threatened to target the planned US missile defence shield in Poland and the Czech Republic if Washington failed to listen to Moscow's concerns.

General Nikolai Solovtsov, head of strategic missile forces, said that such a decision could be taken if the US shield was seen to "undermine the Russian nuclear deterrent capability," the Interfax news agency reported

"I do not exclude... the missile defence shield sites in Poland and the Czech Republic being chosen as targets for some of our intercontinental ballistic missiles," Solovtsov said, according to Interfax.

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