Concerns over a brewing civil war in Egypt emerged Friday as the country faced a weekend of protests marking Islamist President Mohamed Morsi's first year in office.

At least two people were killed Friday – including one American – and scores injured in violence that has the country's top conservative clerics warning of civil war. Protesters attacked offices belonging to the Muslim Brotherhood and its political wing, the Freedom and Justice Party, with some offices set on fire. Before becoming president, Morsi was a top Brotherhood official and he has helped fellow Islamists rise to positions of power.

"Vigilance is required to ensure we do not slide into civil war," read a statement from Al Azhar University, Egypt's top Sunni religious body. But Al-Azhar officials blamed Morsi opponents for the violence, with one calling them "ignorant people" and demanding they stand down.

In a speech Wednesday, Morsi claimed he was open to constitutional reforms and asked for dialogue.

Neither is likely to happen.

Computer science student Mohamed Abdul Munim summed up the views of many Morsi critics during an interview with NBC News.

"We are sure that we will go out and get beaten up by the [Muslim] Brotherhood [but] we are going out despite this," said Munim, 23. "There is no security, there is economic collapse, the electricity cuts off and everybody is suffering. They will say Morsi is not at fault, but electricity didn't cut off when the military governed."

Motorists also are waiting in long gas lines.

Morsi's critics also are angry at the United States, which they see as standing squarely behind the Muslim Brotherhood-dominated government.

Those who can are fleeing the country, packing departing flights out of Cairo's airport, the Associated Press reported, citing unnamed airport officials. They called it an unprecedented exodus by families of government officials, Egyptian Christians and business and diplomatic officials.

Wael Ghonim, the Internet activist credited with helping stoke the 2011 uprising that ultimately ousted Hosni Mubarak, this week called for Morsi's resignation, saying the president broke his promise to build an inclusive government to represent all Egyptians.

The motto was "Our strength, in our unity." But, Ghonim said, the reality has become "Our strength, in our Brotherhood" as the Islamist groups dominates power under Morsi. "[W]e find that we have replaced a ruling party that considered whoever opposes it to be a traitor and an agent with another ruling party that considers whoever opposes it to be a traitor, an agent and a hater of religion."

Egypt "has become very dangerous," Ghonim added, "and all the parties are motivated against each other, and anyone who loves this country must be worried about what is happening, because in the current conflict, regardless of its future victor, Egypt will lose."