Egypt's new military rulers have pledged to enact a smooth transition to civilian rule, amid celebrations marking the country's first day in almost 30 years without Hosni Mubarak as president.

The Supreme Council of the Armed Forces vowed on Saturday to hand power to an elected, civilian government in a statement that came a day after Mubarak was swept from power following an 18-day public uprising.

The military will "guarantee the peaceful transition of power in the framework of a free, democratic system which allows an elected, civilian power to govern the country to build a democratic, free state", a senior army officer announced on state television.

The council also pledged to honour its international treaties - in an apparent nod to the country's 1979 peace treaty with Israel.

"The Arab Republic of Egypt is committed to all regional and international obligations and treaties," the military statement read.

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Binyamin Netanyahu, the Israeli prime minister, welcomed the assurance, saying the "longstanding peace treaty between Israel and Egypt ... is the cornerstone for peace and stability in the entire Middle East".

Later on Saturday, Egyptian state television reported that prosecutors had begun an investigation into three former ministers from Mubarak's government.

Travel bans were imposed on former prime minister Ahmed Nazif and former interior minister Habib al-Adli, who were both sacked by Mubarak before he stepped down from the presidency on Friday.

A travel ban was also imposed on Anas el-Fekky, the information minister, who had been reappointed in a cabinet that had been swiftly sworn in as a concession to protesters. Shortly afterwards, Egypt's current prime minister Ahmed Shafiq told a private Egyptian television station that el-Fekky had resigned and that his resignation had been accepted.

Al Jazeera's Sherine Tadros, reporting from Cairo, said the bans were likely to be welcomed by pro-democracy activists, some of whom vowed to remain in the capital's Tahrir Square until their agenda for democratic reform is fully accepted.

"People out on the streets at the beginning were very much calling for the end of the regime, they were saying they don't want any of these people to remain in Egypt," she said.

"After the step down of President Hosni Mubarak they will be looking for accountability and that is what Egyptian authorities are now providing."

Concerns for the future

Our correspondent said questions now remain over how the military's transition to civilian rule will take place.

"I’m worried about the future," one Egyptian told Al Jazeera. "Nobody knows what's coming. We need to rebuild our country and economy because we are venturing into the unknown."

Despite the uncertainty, celebrations continued in Cairo and other parts of the country a day after Mubarak stepped down, handing power to the military.

Al Jazeera's online producer, Evan Hill, reported some instances of fighting between the army and protesters in Cairo as the military worked to dismantle barricades that protesters promptly put back in place in their effort to remain in the square.

For the most part, however, the day proceeded without any major incidents, following 18 days of rallies in Tahrir Square that culminated in a mass celebration on Friday at the news that Mubarak had stepped down.

Omar Suleiman, the vice-president, announced the news in a televised address on Friday, saying the president was "waiving" his office, and had handed over authority to the supreme military council.

Suleiman's 50-word statement was received with a roar of approval and by celebratory chanting and flag-waving from a crowd of hundreds of thousands in Tahrir Square, as well as by other pro-democracy campaigners who were attending protests across the country.

The highest-ranking figure in Egypt is now Field Marshal Mohammed Hussein Tantawi, the country's defence minister and head of the military supreme council.