The unrest in Egypt has raised international concerns over the country's stability and prompted U.N. Secretary General Ban Ki-Moon to condemn in a statement on Saturday both "violent protests" in reference to Brotherhood's rallies and the authorities' "excessive use of force."
Ban also noted, in an apparent rebuff of Brotherhood demands to reinstate Morsi, that the "political clocks move only forward, not backward" and urged "maximum restraint and shift immediately to de-escalation."
Former President Jimmy Carter expressed deep concern over the violence, saying it is "rapidly eroding the chances for dialogue and a road to reconciliation." Carter added that he is "especially concerned that Egyptians are arming themselves and engaging in inter-communal violence."
In Cairo, the assault on the al-Fath Mosque began on Friday when pro-Morsi protesters and armed men fled into the worship center to avoid angry vigilantes and arrest. They piled furniture in the mosque's entrance to block authorities and enraged anti-Morsi protesters from reaching them.
The mosque served as a field hospital and an open-air morgue as a Brotherhood-called day of protests descended into violence. By daybreak Saturday, security forces and armored personnel carriers had surrounded the mosque and it appeared that military-led negotiations might defuse the standoff.
A post on the Facebook page of the army spokesman, Col. Mohammed Ali, accused gunmen of firing from the mosque at nearby buildings, located on Ramses Square in central Cairo. The upper floors of a commercial building and blood bank towering over the square caught fire during the mayhem, with flames engulfing it for hours.
A Muslim cleric, Sheik Abdel-Hafiz el-Maslami, told The Associated Press that people were afraid to leave the mosque out of fear of detention or being assaulted by the crowd outside. He said there were armed men inside the mosque at one point but protesters had forced them out.