What's next in Cairo?

UPDATE (Aug. 16, 9 a.m. EDT): Despite government orders to use deadly force against anyone threatening police or state institutions, thousands of Muslim Brotherhood supporters took to the streets again today to protest the brutality that began Wednesday. They're calling it a “Day of Rage.”

The official death toll from this week's clashes now stands at 638, with some saying the number could continue to climb.

As protestors poured out of mosques after midday prayers today, security forces sealed off Cairo's main squares and major intersections with armored vehicles and soldiers toting machine guns.

EARLIER STORY: Egyptians began burying their dead today—the morning after the country’s deadliest day since political upheaval erupted more than two years ago. Government officials reported 525 deaths in violent clashes across Egypt on Wednesday, including 43 police officers.

But the death toll likely will climb: The official count only included bodies that had passed through hospitals. Reporters from the BBC and the Associated Press reported seeing at least 200 bodies wrapped in shrouds in a Cairo mosque, and said it wasn’t clear whether authorities had included those bodies among the dead.

By this morning, smoke was still rising from smoldering sites around Cairo, where security forces clashed with supporters of ousted President Mohamed Morsi. The violence began Wednesday morning when police raided two camps filled with thousands of Muslim Brotherhood and Morsi supporters.

The ensuing violence left at least hundreds of demonstrators dead, and injured at least 3,000 people. President Barack Obama condemned the military’s actions in breaking up the camps by force, and called on leaders to find a peaceful resolution.

On the streets of Cairo, a peaceful resolution seemed unlikely in the near future. This afternoon, demonstrators torched two government buildings in Giza, a city just outside Cairo and home to the Pyramids. The Muslim Brotherhood warned of more demonstrations to come, even as Egyptian officials authorized police officers to use deadly force to protect themselves and state institutions from attacks.

Meanwhile, Christians assessed damages at some 25 churches across Egypt. Media reports indicated pro-Morsi supporters had attacked dozens of churches, and set some on fire. The Bible Society of Egypt reported demonstrators had torched two of its storefronts in cities outside Cairo.

For most of the day, many streets in Cairo seemed uncharacteristically quiet, as families stayed home from work, and shops and banks remained closed. Egyptian officials instituted a 7 p.m. curfew for major cities.

In other areas, hundreds gathered for noon prayers at a local mosque near one of the dismantled camps. Some looked under tattered sheets to try to identify the dead, and others vowed to continue protests in a chant that broke out after the noon prayers: “They have the gun but we have Allah.”