Mursi Faces Biggest Test
Thousands of protesters gather in Cairo's iconic Tahrir Square, calling on Egypt's president, Mohamed Mursi, to step down.
The demonstration - one of several across the country - is the biggest challenge yet to the embattled Islamist leader.
Since winning a landmark election last year, Mursi has drawn fire for his handling of the country, which has been plagued by a series of economic and political crises.
"We elected him so that he would provide security, to provide food, to provide electricity, and petrol," says this man. "He hasn't provided anything."
"I have come for one reason only," said another protester. "One way or another Mursi will fall."
Supporters also rallied to show their faith in Mursi, the country's first freely elected leader.
Many have vowed to protect the president, who hails from the Muslim Brotherhood, and there are widespread fears Sunday's demonstrations could turn bloody.
That has prompted the military to beef up security around key buildings, including Cairo's airport.
Already this week, several people, including an American student, have been killed in clashes.