The White House is bracing for what comes next after Egyptian President Hosni Mubarak Friday stepped down after more than 30 years of rule.

"This is not the end of Egypt's transition," said U.S. President Barack Obama in a speech from the White House on Friday. "It's a beginning. I'm sure there will be difficult days ahead, and many questions remain unanswered. But 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."

Obama said the United States would continue to be a "friend and partner to Egypt" and is ready to provide the necessary assistance to pursue a credible transition to a democracy.

Protestors expressed jubilation at the news that Mubarak had stepped down, according to live coverage from Cairo on several U.S. news stations.

Egyptian Vice President Omar Suleiman announced Friday that a high council of the armed forces will administer the affairs of the country. Presumably, the military will rule in the interim before elections can happen in September.

But the hard work starts now, experts said, as it remains unknown who will fill the void. Some fret that the Muslim Brotherhood, a radical Islamist group, could take power, as the organization is said to be the most organized in the country.

Others, however, noted that the group is backed by roughly 15 percent to 20 percent of the population, and this pro-democracy movement is unlikely to back such a group.

Other experts note that it will take time to ensure that free and fair elections can occur and that candidates can emerge.

It also remains unknown what role the Obama administration will play. Will Washington send advisors to help Egypt through this transition, or send delegations? Or will the White House take a more hands off position? Will the United States increase aid to Egypt? How will this impact the region?

Those are among the myriad questions the Obama administration will face as a key regional ally navigates this unprecedented situation.

David Pollock, senior fellow at the Washington Institute, said the key question now is what it means that Egypt's military is taking over, as Egyptian Vice President Omar Suleiman said would happen.

The situation remains unclear, and the United States will need to deal with new partners in Egypt to promote both democracy and common strategy.

"This is a very tricky and uncertain but potentially better situation than the past three weeks of unrest," Pollock said. "One of the most important things to watch is how the Egyptian public reacts."

Neighbors in the region are also likely wondering whether popular upheaval will spread. And in Israel, a U.S. ally with whom Egypt has a peace treaty, is watching the situation carefully, according to news reports.

Global intelligence company Stratfor said in a statement Friday that Suleiman's statement is the clearest indication so far that the military has carried out a coup led by Defense Minister Field Marshal Mohammed Hussein Tantawi.

It remains unclear whether Suleiman will stay on as the civilian head of the army-led government, but so far Egypt is returning to the 1952 model of ruling the state via a council of army officers, Stratfor said in a statement.

"The question now is to what extent the military elite will share power with its civilian counterparts," Stratfor said.

"At a certain point, the opposition's euphoria will subside and demands for elections will be voiced. The United States, while supportive of the military containing the unrest, also has a strategic need to see Egypt move toward a more pluralistic system," Stratfor said.