The resignation of Egyptian leader Hosny Mubarak Friday is only the beginning of a political transition in Egypt and there are "difficult days ahead" as the country tries to map out its future, US President Barack Obama said.
Obama spoke at the White House hours after Mubarak stepped down, following more than two weeks of mass protests demanding an end to his 30-year authoritarian rule.
"This is not the end of Egypt's transition. It's a beginning," Obama said. "I'm sure there will be difficult days ahead, and many questions remain unanswered."
"I am confident that the people of Egypt can find the answers, and do so peacefully, constructively and in the spirit of unity that has defined these last few weeks," he added.
Egyptian Vice President Omar Suleiman announced earlier Friday that Mubarak had stepped down and handed power to the military, sparking widespread celebrations on the streets of Cairo and other countries.
Obama called on the military to ensure that a transition to free and fair elections "is credible in the eyes of the Egyptian people."
That includes protecting the people's rights, lifting the emergency law, revising the constitution and ensuring that reforms are "irreversible," Obama said. The transition must also bring all segments of Egyptian society into the process, he added.
"Egyptians have made it clear that nothing less than genuine democracy will carry the day," Obama said.
Since the demonstrations began the Obama administration has spoken out for the rights and democratic aspirations of the Egyptian people, but has stopped short of backing calls for the resignation of Mubarak, who was seen as a close US ally in the region and a pillar of stability.
But Washington had also been urging Mubarak to implement political and economic reforms and an orderly democratic transition. Obama had twice spoken to Mubarak during the crisis, while Vice President Joe Biden was in contact with Suleiman, , dpa reported.
Obama was informed in the morning that Mubarak had intended to resign and watched Suleiman's announcement on television, CNN reported. Obama spent hours with his foreign policy aides Friday morning discussing the rapidly unfolding events in Egyupt, White House spokesman Robert Gibbs said.
Obama had planned on making a statement earlier but that was delayed until later in the afternoon.
"There are very few moments in our lives where we have the privilege to witness history taking place. This is one of those moments," Obama said. "The people of Egypt have spoken, their voices have been heard, and Egypt will never be the same."