WASHINGTON -- President Bush welcomed seven former Soviet-dominated nations into NATO as "full and equal partners" on Monday and said the Western alliance was stronger because of their presence.
Under a bright sun on the White House South Lawn, Bush stood with the prime ministers of Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia. Hundreds of people cheered. Some waved flags of the new member nations, whose addition expands the alliance to 26 countries.
A military honor guard carried the flags of the NATO countries.
Fifty-five years after NATO's birth, Bush recalled that the seven new members were "captives to an empire" when the alliance was formed.
"They endured bitter tyranny. They struggled for independence. They earned their freedom through courage and perseverance and today they stand with us as full and equal partners in this great alliance," he said.
The new members will take part in their first meeting Friday in Brussels, Belgium. Three other nations -- Albania, Croatia and Macedonia -- still hope to join.
"The door to NATO will remain open until the whole of Europe is united in freedom and in peace," the president said.
Pointing to the nations' history of domination, Bush said, "As witness to some of the great crimes of the last century, our new members bring moral clarity to the purposes of our alliance.
"They understand our cause in Afghanistan and in Iraq," the president said, "because tyranny for them is still a fresh memory."
"They know that aggression left unchecked can rob millions of their liberty and their lives," Bush said. "And so now as members of NATO they are stepping forward to secure the lives and freedoms of others."
NATO has agreed to include the Baltic states under its air defense shield, planning to enforce it by stationing four F-16 fighter planes in Lithuania.
NATO secretary-general Jaap de Hoop Scheffer told reporters at a breakfast interview Monday that fighter planes would begin "air policing" over the Baltic states at the moment their NATO membership took effect Monday, and that he explained the policy to Russian Foreign Minister Sergei Lavrov two weeks ago.
"I think that the Russian Federation has very well understood that NATO has, of course, no ulterior motives by air-policing its airspace," de Hoop Scheffer said, adding that NATO has a solid relationship with Russia. "I think that NATO and Russia will further build on this partnership."
Some new members, such as Romania and Bulgaria, have military bases and training ranges that the United States would like to use or have access to in times of crisis. Their presence could mean a decided shift in NATO's decision-making processes, particularly within the governing councils, said Marine Gen. James Jones, the supreme allied commander in Europe.
"It will be a different organization," Jones told reporters Friday. "The eastern European influence will change the voting demographics; they'll bring different views."
Russia has cast a wary eye toward the expansion of NATO, which was established during the Cold War to shield the United States, Canada and 10 European countries from various threats, including the Soviet Union's military might.
U.S. officials have minimized worries that NATO expansion could cause tensions with Russia, but President Vladimir Putin's government has warned that Moscow intends to take steps to defend itself should it perceive NATO's eastward push as a threat.
Lavrov said Monday that he hopes Friday's meeting will yield an agreement that new NATO members will join the revised Conventional Forces in Europe Treaty, "and pledge to abide by its provisions until they do so."
Konstantin Kosachyov, head of the international affairs committee in Russia's lower house of parliament, said there was "an unfriendly character" to NATO expansion and that if significant NATO bases appear near Russia's border, "then we can't exclude that Russia will consider the possibility of taking corresponding action."
Russia is not a member of NATO but has accepted an invitation to participate in talks at NATO's headquarters in Brussels on Friday.