Tens of thousands of Egyptians have packed Cairo's Tahrir Square to protest the ruling military's bid to grab new powers, while ex-president Hosni Mubarak was moved to a military hospital from prison after reportedly suffering a stroke.
Interior Ministry spokesman Alaa Mahmoud said Tuesday the 84-year-old Mubarak was moved by ambulance from the hospital in Torah Prison to nearby Maadi Hospital in southern Cairo.
Earlier, Egypt's state news agency said Mubarak's health had rapidly deteriorated, with his heart stopping briefly. The ousted leader was sentenced to a life term earlier this month for failing to stop the killing of protesters during last year's uprising.
Meanwhile, on the streets, demonstrators from across the political spectrum packed central Cairo to protest a declaration by Egypt's ruling generals extending their grip on power.
Egypt's Muslim Brotherhood has vowed to challenge the military's recent moves giving it and the courts final say over much domestic and foreign policy and the constitutional drafting process. The Brotherhood's call for mass protests Tuesday was joined by the April 6 Youth Movement and several trade unions
This comes after the Brotherhood declared victory in the country's first freely contested presidential election.
The ruling Supreme Council of the Armed Forces vowed Monday to honor its promise to hand over power to Egypt's newly elected president by the end of the month. The announcement comes a day after the SCAF declared a new interim constitution, diminishing the powers of the eventual election winner.
In Washington, both the State Department and the Pentagon - which oversees the close military links between the two countries - voiced concerns over the recent developments.
State Department spokeswoman Victoria Nuland said the U.S. will hold the SCAF to its promises for an "inclusive constitutional drafting process, the timely seating of a democratically elected parliament, and the swift, permanent transfer of power to a civilian government."
At a news conference Monday, military council members did not comment on unofficial election results showing Muslim Brotherhood candidate Mohammed Morsi had defeated his rival, former prime minister Ahmed Shafiq, in the presidential runoff.
Both candidates claimed victory, but the detailed, precinct-specific nature of the Brotherhood's tallies convinced many analysts its projections showing Mr. Morsi winning 52 percent of the vote were accurate. Aides of the establishment-backed Shafiq disputed the claim.
Election officials will not formally confirm the results until later in the week.
The interim constitution grants the generals legislative powers until a new lower house of parliament is elected to replace the Islamist-dominated People's Assembly dissolved by the country's top court last week. It rules that no election can be held until a military-appointed panel writes a permanent constitution whose articles the generals can veto.
But the Brotherhood-affiliated speaker of the now defunct assembly, Saad el-Katatni, said a panel appointed by the body last week will go ahead with plans to write a permanent constitution. The Brotherhood has refused to recognize the dissolution of parliament.
Turnout in the two-day presidential runoff that ended Sunday appeared lower than the 46 percent figure reported in last month's first round - a sign of declining public morale as the military tightened its grip on power in recent days.