WASHINGTON (AP) -- Former President George W. Bush is praising the Arab spring movement and says the U.S. shouldn't fear the spread of freedom, even if it doesn't know what policies newly liberated countries will pursue.

Bush says uprisings in Tunisia, Egypt and Libya marked the broadest challenge to authoritarian rule since the fall of the Soviet Union. He says some fear what the regime changes will mean for U.S. foreign policy, but that America should always stand for freedom.

Bush says the U.S. doesn't get to choose where or when a "freedom revolution" begins, just which side it's on. He says the U.S. should help countries put firm democratic reforms in place after a revolution to prevent backsliding or corruption.

Bush spoke Tuesday in Washington at an event for his presidential institute.