U.S. Secretary of State Hillary Rodham Clinton on Wednesday, March 16, toured Cairo's Tahrir Square, the epicenter of the popular uprising that toppled Egypt's longtime autocratic leader last month.

"It's just a great reminder of the power of the human spirit and universal desire for freedom and human rights and democracy," Clinton said. "It's just thrilling to see where this happened."

Surrounded by a heavy contingent of U.S. and Egyptian security guards, Clinton smiled, waved and shook hands with the Egyptian citizens who thronged her during her unscheduled 15-minute stroll through the square.

"To see where this revolution happened, after all that it has meant to the world, is extraordinary for me," she said before entering a meeting with interim Prime Minister Essam Sharaf.

Clinton's two-day visit to Egypt is aimed at encouraging the Egyptian people and their transitional leaders to hold true to the ideals of democratic reforms that propelled the revolution.

She is the highest-ranking U.S. official to visit Egypt since President Hosni Mubarak was ousted last month and she has pledged America's support for the transition. Her trip underscores the Obama administration's concern that gains made since last month's ouster of President Hosni Mubarak may be lost to impatience or a hijacking of the political system by extremists.