The Russian Foreign Ministry is accusing the U.S. of not being transparent enough about its planned missile defence system in Eastern Europe.

Moscow says it will be forced to take its own defensive steps if America deploys its proposed anti-missile shield.

Deputy Foreign Minister Sergey Kislyak says Russia will do whatever is necessary to ensure its security.

“If we see that the evolvement of the system could undermine our missile deterrent capability, then our military will have to take steps to neutralise the threat,” Kislyak said.

Last week the U.S. Secretary of State, Condoleezza Rice, signed a deal with the Czech Republic to place a radar base in the former Soviet-bloc country.

But before it can come into effect, the treaty has to be passed by the Czech parliament.

The signing of the agreement provoked protests in Prague as hundreds of peace activists took to the streets.

Earlier this month Poland rejected an initial offer by the U.S. to locate 10 interceptor missiles there. However, Warsaw said it's ready to continue talks with Washington on the issue.

Russia strongly opposes Washington’s plans and regards the placement of U.S. military hardware near its borders as a threat to its national security.