UN Secretary-General Ban Ki-moon has expressed alarm at the escalating unrest in Egypt.
In a statement issued on August 17 by his spokesman, Ban urged an end to violent protests and cited what he called the "excessive use of force" in putting them down.
Ban condemned attacks on churches, hospitals, and other public facilities.
Meanwhile, the European Union says it plans to review its relationship with Egypt. In a statement, European Council President Herman Van Romuy and European Commission President Jose Manuel Barroso called on all sides in Egypt to refrain from violence and to show restraint.
The statement said the EU will "urgently review" its relations with Egypt within the next few days and will "adopt measures aimed" at preventing further violence.
Earlier, Egyptian security forces cleared out Islamist supporters of ousted President Muhammad Morsi from a mosque in the capital, Cairo.
The action came after a standoff that included exchanges of gunfire.
More than 750 have been killed since protests and clashes erupted across Egypt after security forces cleared two camps of Morsi supporters in Cairo on August 14.
The Muslim Brotherhood, of which Morsi is a senior leader, has vowed to continue daily protests.
The government says it is considering legally dissolving the Brotherhood.
Interim Prime Minister Hazem el-Beblawi said there could be no reconciliation "with those who have broken the law."
"There is no reconciliation with those whose hands are covered in blood. There is no reconciliation for anyone who has raised arms against the country, against its people," he said.
The Interior Ministry said police had arrested more than 1,000 Muslim Brotherhood "elements" following riots on August 16. The group said daughters and sons of the leadership had been targeted in an effort to gain leverage over the organization.
The state news agency said 250 Brotherhood followers faced possible charges of murder, attempted murder, and terrorism.
The government has ordered a dawn-to-dusk curfew that looks set to last until the middle of September, leaving the normally crowded streets of major cities eerily deserted at sundown.
In a sign things may be returning to normal, banks were due to reopen on August 18 for the first time since the August 14 bloodshed, and the stock exchange will also resume business, with trading cut to three hours from four because of the instability.
With reporting by Reuters and AP