CAIRO AND WASHINGTON — Egypt's new military rulers swiftly reassured citizens and strategic allies alike of their commitment to civilian control and stability, but with ecstatic crowds still in the streets it was far from certain that the generals had the vision or will to transform the Arab world's most populous nation into a vibrant democracy.
The effort to calm anxieties came a day after a popular uprising forced President Hosni Mubarak to resign after 30 years of autocratic rule. Egyptians sang, cheered and danced into the night Saturday, even as tanks, armored cars and combat troops guarded key buildings and intersections.
The military pledged to oversee a transfer to civilian authority and said it was committed to observing Egypt's international treaties, a statement welcomed by Israel, which was concerned about the status of its 1979 peace agreement with Cairo.
Leaders of the pro-democracy movement that forced Mubarak from power said they had faith in the army but they would hold more protests if the military went back on its word. The group demanded the repeal of Egypt's emergency law, the formation of a unity government, the disbanding of the parliament and the establishment of a committee to write a new constitution.
"The army has met our demands," said Google executive and political activist Wael Ghonim. "I think it's over. They see the Egyptians are no longer going to accept a dictatorship."
But analysts in Cairo, Washington and Tel Aviv say the situation remains too volatile to be sure that the military council will ultimately permit free elections, accede to civilian control and allow transparency.
No popular civilian leaders or independent political parties were allowed to emerge during Mubarak's long tenure. His departure has left a political void, and some analysts fear that the generals may seek to stifle any threat to the status quo.
Moreover, Egypt's 480,000-member professional military is dwarfed by the paramilitary national police and the state security and intelligence agencies, which enforced Mubarak's repressive policies, including arbitrary arrests and torture. A power struggle may emerge if loyalists seek to hijack the process.
Post-Mubarak Egypt could follow the path of Turkey and Indonesia, Muslim nations in which the army remains strong but democratic reforms have flourished. Or it could go the way of Pakistan, where military and intelligence services hold the levers of power.
A spokesman for the Supreme Council of the Armed Forces, which now in effect rules Egypt, said on state television that the military would work to ensure "a peaceful transition of power ... to achieve a civil authority that will build a free, democratic nation."
The spokesman, Gen. Mohsen Fangari, also said the council would observe all of Egypt's international treaties.
Abdel Rahman Abdel Halem, a retired Egyptian general, said he believed the new leaders would keep their promise.
They have "been keen to reiterate their intention of supporting a transition toward civilian control, and that can be a good sign that they don't want to keep hold on power," he said. Civilian rule, he added, "will not contradict their dominant position, at least for now anyway."
Ammar Ali Hassan, a political analyst and former Egyptian military officer, said the army was considering adding civilians to the Supreme Council. Newly energized political activists wouldn't allow the military to keep power, and foreign allies wouldn't accept it, he said.
"Now the army needs to come out with a statement that would include a time frame as to when exactly it will cede power," he added.
Others fear that the army will be reluctant to share power.
"It will be a long while before a civilian government can rule without full support of the military, and even longer before the military takes orders from a civilian government," said Sheila Carapico, chair of the political science department at the American University in Cairo.
Jon Alterman, director of the Middle East program at the nonpartisan Center for Strategic and International Studies in Washington, said the military was torn about what it wanted.
"They're not comfortable in politics," he said. "But they're not comfortable with what an open political system would look like."
Men with a military background have ruled Egypt since 1952. The armed forces are significant players in the economy. Military-owned commercial companies produce olive oil, cement, televisions, clothing and more. They are a revered part of the social fabric. They received unstinting support from Mubarak, and have gotten $1.3 billion a year from the Pentagon.
Two members of the Supreme Council appeared at the center of the drama. Field Marshal Mohamed Hussein Tantawi, the defense minister, and Lt. Gen. Sami Hafez Enan, chief of staff of the armed forces, gained credibility by mingling with protesters at Tahrir Square, and more important, ordering soldiers not to fire on the demonstrators.