"Now it is clearly understood in the alliance that the challenges of the 21st century, the threats of the 21st century, make it necessary to have missile defense that can defend the countries of Europe," Rice told reporters at the NATO summit.
Progress on missile defense represented perhaps the biggest boon to Mr. Bush from the NATO summit. Russia has fiercely opposed it.
Rice also noted that NATO has "also asked Russia to stop its criticism of the alliance effort and to join in the cooperative efforts that have been offered to it by the United States."
A NATO statement calls on the alliance to explore ways in which the planned U.S. project, to be based in Poland and the Czech Republic, can be linked with future missile shields elsewhere. It says leaders should come up with recommendations to be considered at their next meeting in 2009.
The U.S. plan calls for 10 interceptor missiles based in Poland and a tracking radar site in the Czech Republic.
At a news conference in Bucharest on the sidelines of the NATO summit, Czech Foreign Minister Karel Schwarzenberg announced that negotiations with the Americans have been successfully completed and that a deal would be signed in early May.
The Poles have yet to agree to the plan, but in Warsaw on Thursday, talks picked up between Polish and U.S. officials about it.
The backing from NATO and the announcement with the Czechs provides Mr. Bush with a powerful leg up in his negotiations with Moscow over the issue.
Mr. Bush is seeing Russian President Vladimir Putin twice this week - during the summit and Sunday in Sochi, Russia. White House officials have talked optimistically in recent days that the weekend meeting could break the missile defense logjam.
"I think we can probably look for a deal" by the time Mr. Bush and his counterpart President Vladimir Putin hold their bilateral meeting this weekend, reports b>CBS News senior White House correspondent Bill Plante.
Rice said she was hopeful that Mr. Bush and Putin would agree on a broad framework for cooperation between the countries, but it was still unclear whether they would reach a deal on missile defense. The administration has worked to allay Russian leaders' fears that the system is a threat to them.
"We hope that we can move beyond that to an understanding that we will all have an interest in cooperation on missile defense," Rice said. "But we will see."
On Afghanistan, Mr. Bush did win a commitment of more troops to Afghanistan's most dangerous areas, although his national security adviser acknowledged more needs to be done.
"We are not at the level of what at this point in time our commanders looking forward say we need and that's why we said more to do," Stephen Hadley said at the briefing with Rice.
French President Nicolas Sarkozy said France will send as many as 1,000 troops to the eastern part of the country, freeing up some U.S. forces to move to the south. Canada had threatened to pull its soldiers out of the volatile south, the front line in the fight against a resurgent Taliban and al Qaeda forces, unless it received 1,000 reinforcements from another ally.
On NATO expansion, Mr. Bushin his drive to have the alliance include Ukraine and Georgia, two former Soviet republics.
"NATO's door must remain open to other nations in Europe that share our love for liberty and demonstrate a commitment to reform and seek to strengthen their ties with the trans-Atlantic community," Mr. Bush said in brief remarks at an alliance meeting. "We must give other nations seeking membership a full and fair hearing."
Fellow NATO leaders, fearing a clash with Moscow, rejected Mr. Bush's appeal to allow the countries to get on a path toward membership. But Hadley said the president plans to make a new pitch before he leaves office in January. The United States expects to raise the matter at a meeting of NATO foreign minister in December, Hadley said.
The president expressed regret that NATO also declined to offer full membership at this meeting to Macedonia. The invitation was blocked by Greece, which says the country's name implies a territorial claim to a northern region of Greece, also called Macedonia.
"Macedonia's made difficult reforms at home," Mr. Bush said. "It is making major contributions to NATO missions abroad. The name issue needs to be resolved quickly so that Macedonia can be welcomed into NATO as soon as possible."
Albania and Croatia were invited to join the alliance, now currently at 26 members.
Progress on missile defense represented perhaps the biggest boon to Bush from the summit. NATO leaders were adopting a statement that "ballistic missile proliferation poses an increasing threat to allied forces, territory and populations" and that the U.S.-led system would help protect allies.
The statement calls on all NATO members to explore ways in which the planned U.S. project can be linked with future missile shields elsewhere The plan calls for 10 interceptor missiles based in Poland and a tracking radar site in the Czech Republic.
Russia charges the intent of the system would be to weaken its nuclear deterrent capabilities and upset the balance of power in Europe. Mr. Bush has denied that, saying the facilities are designed to protect Europe against a potential missile attack - or even just nuclear blackmail - by Iran. The dispute has become heated at times, with confrontational, Cold War-style rhetoric from Moscow.
Mr. Bush essentially has rejected Russia's suggestion that the U.S. substitute an early warning radar in Azerbaijan for the Europe-based system. But U.S. officials have been working to come up with a list of concessions and assurances that could resolve Moscow's fears, such as offering to let Russia share in the information the system collects and promising not to activate it without a verifiable threat.