U.S. President George W. Bush is welcoming two new members to NATO. VOA's Paula Wolfson reports Mr. Bush hailed the transformation of the Balkans in a speech in a town square in the Croatian capital, Zagreb.

Croatians filled St. Mark's square Saturday to celebrate, standing in front of the great stone cathedral that has watched over Zagreb for centuries.

President Bush told the crowd, "The great church in this square has stood since the Middle Ages. Over the centuries it has seen long dark winters of occupation and tyranny and war. But the spring is here at last."

Fresh from the NATO summit that invited Croatia to join the alliance, President Bush talked about how that country has left a troubled past behind to become a free state.

"The Croatian people have overcome war and hardship to build peaceful relations with your neighbors and to build a maturing democracy in one of the most beautiful countries on the face of the earth," said Mr. Bush.

Croatia was one of three Balkan countries deemed by NATO leaders to meet the criteria for membership. Two - Croatia and Albania - are beginning the admission process immediately. The third - Macedonia - must wait until it settles a name dispute with its neighbor, Greece.

Leaders of all three countries were on hand in Zagreb for the celebration. As they looked on, President Bush made a vow.  He said, "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 noted that Croatia, Albania and Macedonia have all deployed troops to Afghanistan, and Croatian and Albanian forces have served in Iraq. He said as countries that have experienced life under repression, they are serving as an example to others.

"There are those who actually wonder if people were better off under their old tyranny. You can tell them that freedom is the only real path to prosperity, security and peace," said the U.S. president.

From Croatia, Mr. Bush heads to the Russian Black Sea resort of Sochi for a final meeting with Vladimir Putin before he leaves the Russian presidency.

Their talks - at a Russian presidential retreat - are expected to focus on U.S. plans to put a missile defense system in central Europe.

Russia is opposed to the idea, saying it could lead to a new arms race. President Bush has tried to reassure Moscow, saying the system is designed to counter a threat from rogue states in the Middle East, such as Iran.

U.S. Secretary of State Condoleezza Rice recently met with Russian leaders in Moscow and says the U.S. laid out ideas the Russians found useful.  She said, "We hope that we can move beyond that to an understanding that we will all have an interest in cooperation on missile defense, but we will see. "

A senior White House official says President Bush has described the session in Sochi as a meeting of "two old warhorses" - a reference to a long working relationship that is nearing an end as both men prepare to leave the presidency of their respective nations.