While in the Czech capital, Mr. Bush is expected to present his case for a strong stand on disarming Iraq and to discuss the fight against terrorism.
But, National security Adviser Condoleezza Rice says Iraq will not dominate the summit. She says the planned expansion of NATO is part of what she called the alliance's "historic transformation" to better respond to the threats of the 21st century.
The two-day summit, beginning late Wednesday, will touch on modernizing NATO's military to deal with changing international threats. Mr. Bush says NATO needs to change its military strategy and focus on the true threat it now faces -- which he says is global terrorism. He also says he will seek to reassure Russia that NATO's eastward expansion will not threaten Moscow's security.
Mr. Bush also says he believes the seven countries invited to join NATO will add vigor to the alliance. He says those countries will contribute both militarily and through their love of freedom.
The seven countries being invited to join NATO are Romania, Bulgaria, Latvia, Lithuania, Estonia, Slovenia and Slovakia. It is only the second time since the end of the Cold War that new countries have been offered membership in the alliance.
Following the NATO summit, Mr. Bush travels to St. Petersburg, Russia, for a meeting with Russian President Vladimir Putin. Their talks are likely to include the conflict in Russia's breakaway Chechen Republic. He then stops in Lithuania and Romania, before returning home Saturday.