Pro-Morsi supporters declared Friday a "Day of Rage" planning mass protests in the wake of a military crackdown that killed 638 people and injured over 3,000.
The Muslim Brotherhood, which supports ousted President Mohammed Morsi, organized the protests.
In Cairo, more demonstrations led to bloodshed as protesters clashed with police and soldiers and large crowds swarmed onto streets and bridges.
Ramses Square, where the group had urged its supporters to converge on, was attacked with tear gas and live ammunition by snipers and police, according to ABC News.
Protesters and residents of the neighborhoods they marched by exchanged gunfire and birdshot as tanks blocked key roads and key junctures.
The violence spread to Egypt's Christian community Friday. A Cairo church was fire bombed and parishioners say it was attacked by the Muslim Brotherhood.
Protesters have since set up a field hospital in Al Fath Mosque.
The Egyptian military remains under orders to use deadly force if troops or government facilities come under attack.
The Muslim Brotherhood was also the target of Wednesday's violence. Hundreds were killed when the Egyptian military moved in and broke up two protester encampments that had been in place for weeks.
The crackdown prompted President Barack Obama to cancel a planned military exercise with Egypt and call for calm from both sides.
"The United States strongly condemns the steps that have been taken by Egypt's interim government and security forces," President Barack Obama said. "We deplore violence against civilians. We support universal rights essential to human dignity, including the right to peaceful protest."The $1.3 billion aid from the U.S. to Egypt and its military remains intact.
A White House adviser says cancelling the aid is a difficult step to reverse and would cause a fundamental change in the relationship between Egypt and the U.S.
The president, however, said American cooperation with the Egyptian government cannot continue when civilians are being killed in the streets.
Meanwhile, other Muslim countries in the region have weighed in. Turkey continues to criticize the military crackdown in Egypt while Saudi Arabia is urging Egyptians to support the police and authorities.
The White House is concerned the growing violence and instability in Egypt could spread across the region. Delivery delays and price spikes are anticipated since oil is shipped through the Suez Canal. There are also reports of terrorist activity in the Sinai Peninsula bordering Israel.
ABC News and The Associated Press contributed to this report.
