The Czech Republic said on Tuesday it would not be intimidated by Russia over plans to site parts of a U.S. missile defence system on its soil, and said attempts at “blackmail” by Moscow would backfire.

the Reuters news agency quoted Czech Foreign Minister Karel Schwarzenberg sas saying that threats by Russian officials over the plans, which would involve placing a radar system on Czech territory and a missile battery in Poland, would only make Czechs more determined to defend themselves.

Russia’s strategic forces commander, General Nikolai Solovtsov, said on Monday that Russia would be capable of firing missiles at the Czech Republic and Poland if the ex-communist states agreed to host the U.S. defence system.

“The Czechs will now think the shield is even more necessary,” Schwarzenberg told Reuters on the sidelines of a business conference in Warsaw.

“We have quite an experience with Russians. You have to make clear to them you won’t succumb to blackmail. Once you give in to blackmail, there’s no going back. We have to be strong.”

The United States wants Poland and Czech Republic to host elements of its multi-billion dollar global system designed to counter missiles fired by what Washington calls “rogue states” such as Iran and North Korea.

Moscow views the system as an attempt to shift the post-Cold War balance of power, and relations between Moscow and Washington have soured since the announcement of the U.S. plans.

Both the Polish and the Czech prime ministers have said their countries would likely say accept the installations, which would tie their interests to Washington in the long term and bolster their security.

Polish Prime Minister Jaroslaw Kaczynski told Polish radio on Tuesday the comments by Solovtsov were “an attempt to scare”.

Czech Prime Minister Topolanek summoned Russia’s ambassador in Prague for “consultations” to take place later this week, a spokesman to Topolanek said.