President Bush has claimed Russia has "derailed" democratic reforms as tensions grow over plans to build a US missile defence shield in Eastern Europe.
Czech President Vaclav Klaus (r) and President George W. Bush in Prague today
Speaking at a "pro-democracy conference" organised by former Czech president Vaclav Havel and ex-Soviet dissident Natan Sharansky in Prague today, Mr Bush called for democratic reforms in Russia and China.
Mr Bush said: "In Russia, reforms that once promised to empower citizens have been derailed, with troubling implications for democratic development."
However, Mr Bush insisted the United States has strong working relationships with both Russia and China. He said: "Our friendship with them is complex. In the areas where we share mutual interests, we work together. In other areas, we have strong disagreements."
Mr Bush added: "Part of a good relationship is the ability to talk openly about our disagreements. So the United States will continue to build our relationships with these countries, and we will do it without abandoning our principles or our values."
Russian leader Vladimir Putin has reacted furiously to a US plan to site a radar system in the Czech Republic and missile interceptors in Poland, warning that Russia will target its missiles on Europe, as it did in the Cold War, if Washington goes ahead.
Mr Bush, in Prague ahead of a Group of Eight summit in Germany where he will see Mr Putin, said the missile shield was intended to protect against threats from "rogue" regimes and repeated his call for Moscow to participate in its development.
The increased tensions between Russia and the United States have prompted concerns among US allies.
Mr Bush sought to dispel concerns that countries cooperating with the United States on the missile shield would be caught up in tensions with Russia.
"The Cold War is over. It ended. The people of the Czech Republic don't have to choose between being a friend of the United States or a friend with Russia, you can be both," Mr Bush said.
Apart from seeing Mr Putin at the June 6th-8th summit, Mr Bush has also invited the Russian leader to his family's retreat in Maine next month.
Mr Bush said his message to Mr Putin at those meetings would be: "You shouldn't fear a missile defence system. As a matter of fact why don't you co-operate with us on a missile defence system, why don't you participate with the United States?"
The missile defence system was a "purely defensive measure, aimed not at Russia but at true threats," Mr Bush said.
Agencies