US President George W. Bush celebrated NATO's expansion into former communist territory on Saturday and urged further enlargement, highlighting differences with Moscow hours before final talks with outgoing Russian President Vladimir Putin. Bush congratulated Croatia and Albania - both of which were under Moscow's Cold War-era influence - for the invitations to join NATO they won a day earlier at the military alliance's summit in Bucharest, Romania. He urged a similar welcome for Macedonia, which snagged on Greek objections. The president was reinforcing that message immediately after his speech in a public square here by honoring the newest members of NATO's club over lunch. Bush called the invitation to join NATO "a vote of confidence that you will continue to make necessary reforms and become strong contributors to our great alliance." "Henceforth, should any danger threaten your people, America and the NATO alliance will stand with you and no one will be able to take your freedom away," he said to cheers from an audience of thousands packed into St. Mark's Square, used as the site of the inauguration of every Croatian leader for the past 700 years. Such praise for the spread of democracy on Russia's doorstep - and for the promise of Western military protection for that freedom - was not likely to be cheered in Moscow, however. Bush's focus on freedom comes as his administration continues to harshly criticize increasing Kremlin authoritarianism. So, even as Bush has sought in recent days to downplay tensions between the United States and Russia, he used his overnight stay in Croatia, as well as one in the former Soviet republic of Ukraine earlier in his weeklong trip, to showcase some of the differences that have caused those tensions. By evening Saturday, Bush was to be at Putin's summer home at the Black Sea resort of Sochi. The two are to cap an often contentious seven-year relationship that will come to an end when Putin leaves office next month. They hope to produce a new "strategic framework" to guide relations to a less rocky future beyond their time in office.