US President George W Bush is in Prague where he is expected to give a speech criticizing what he sees as Russia's growing authoritarianism.

Mr Bush, en route to the G8 summit in Germany, is visiting the Czech Republic and then Poland - two countries where the US seeks to build a missile shield.

Russian President Vladimir Putin has threatened to aim weapons at Europe if the US sets up a missile shield.

His words have widely been received as recalling the rhetoric of the Cold War.

White House officials insist that President Bush's speech is not about Russia but rather renewing his commitment to spreading freedom and democracy.

However, the BBC's Jonathan Beale, who is travelling with Mr Bush, says the president is expected to talk about the difficulties of promoting democracy in countries such as Russia and highlight concerns about the Kremlin's tightening grip on power.

Washington has dismissed talk of a new Cold War but says the rhetoric coming out of the Kremlin has worrying echoes of that era. It wants the words toned down.