US President George W. Bush risked fueling tensions with Russia on Tuesday, saying Moscow had "derailed" once-promising democratic reforms. In a speech celebrating democracy's progress around the globe - and calling out places where its reach is either incomplete or lacking - Bush said that free societies emerge "at different speeds in different places" and have to reflect local customs. But he said certain values were universal to all democracies, and rapped several countries for not embracing them. "In Russia, reforms that once promised to empower citizens have been derailed, with troubling implications for democratic development," Bush said, speaking at a democracy conference in Prague organized by former dissidents. The US president asserted that this discussion of democratic backsliding in Russia under the leadership of President Vladimir Putin was just one part of a strong relationship. "America can maintain a friendship and push a nation toward democracy at the same time," Bush said. But the lecture, however gentle, was not likely to be well-received by Putin, already riled over what he sees as unwelcome meddling by the United States in Russia's sphere of influence. Most recently, Moscow has become increasingly irritated by US plans to build a missile shield in Eastern Europe, on Russia's doorstep. US officials have been alarmed by threatening statements from Putin and others over the proposed network. Russia believes the system - with a radar base planned for the Czech Republic and interceptor missiles in neighboring Poland - is meant for it. Putin has said he has no choice but to boost his nation's own military potential in response. Putin warned over the weekend that Moscow could take "retaliatory steps" including aiming nuclear weapons at US military bases in Europe. China on Tuesday joined Russia in saying the shield could touch off a new arms race. "Part of a good relationship is the ability to talk openly about our disagreements," Bush said in the speech at Czernin Palace. "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." Bush said this same approach applied to other allies with difficult democratic records, naming Egypt, Saudi Arabia, Pakistan and China. "China's leaders believe that they can continue to open the nation's economy without also opening its political system," Bush said. The conference was hosted by Natan Sharansky, a former prisoner of the Soviet regime who has continued to champion freedom, and former Czech President Vaclav Havel, who led the Velvet Revolution that ended communism in the former Czechoslovakia in 1989. Bush planned to meet with current and former dissidents from around the world. With the Iraq war raging and that country in disarray, critics say there is widespread skepticism worldwide about Bush's "freedom agenda" - the byproduct of his promise to advance democracy in every corner of the globe. But Bush claimed the mantle of democratic warrior. "I pledged America to the ultimate goal of ending tyranny in our world," he said. "Some have said that qualifies me as a dissident president. If standing for liberty in the world makes me a dissident, then I'll wear the title with pride." Earlier, Bush and the Czech Republic's leaders defended the plans for the missile shield here against fierce opposition the local population as well as Russia. "The people of the Czech Republic don't have to choose between being a friend of the United States or a friend with Russia," Bush said at a joint appearance with Czech Prime Minister Mirek Topolanek and President Vaclav Klaus in the medieval Prague Castle. "You can be both. We don't believe in a zero-sum world." Standing on soil that was in the Soviet orbit less than 20 years ago, Bush made a declaration not thought necessary for decades: "The Cold War is over." The once-obvious statement has been rendered less so lately amid an escalating war of words between Washington and Moscow. So far, the Bush administration has mostly held its rhetorical fire, giving muted reaction such as calling Putin's remarks "not helpful" and repeating its insistence that the network is meant to protect NATO allies against a missile launch from Iran, not Russia. US officials do not want to give Putin the satisfaction of appearing to be engaged in a dispute among equals with the world's only superpower. But the system is unpopular in the Czech Republic, too, among its citizens if not its leaders. People fear becoming a terrorist target, and they worry about Russia's wrath, as well. So Bush, Topolanek and Klaus sought to calm those fears, with remarks aimed as much at the wary Czech people as at Russia. Bush said he would make his case directly to Putin on Thursday when they meet on the sidelines of the Group of Eight summit in Germany. "My message will be Vladimir - I call him Vladimir - that you shouldn't fear a missile defense system," Bush said. "As a matter of fact, why don't you cooperate with us on a missile defense system? Why don't you participate with the United States?" Klaus applauded Bush's promise to make "maximum efforts" to explain his position to Putin. "We have pointed it out to our guest that it is very important that we win maximum support for this project of the Czech Republic," Klaus said. In Poland, there was support for Bush as well. From Prague, Bush was traveling to Germany's Baltic Sea resort town of Heiligendamm for three days of meetings between the leaders of the world's eight major industrialized democracies. The rest of his eight-day European trip was to include stops in Poland, Italy, Albania and Bulgaria.