Cairo is bracing for a day of mass protests Friday by supporters and opponents of ousted president Mohamed Morsi, with both sides promising to march peacefully.
Morsi's Muslim Brotherhood is refusing to back down from demands that he be reinstated. It strongly opposes plans for a transitional government.
A Brotherhood spokesman says that the group will keep pressuring the leaders of what he calls a military coup with sit-ins and million man marches. He says the movement believes in non-violent, democratic, and peaceful change.
Meanwhile, the U.S. State Department says the arrests of Brotherhood leaders are not in line with the national reconciliation the interim Egyptian government says it wants.
Spokeswoman Jan Psaki says if politicized arrests and detentions continue, it would be hard to see how Egypt can move forward.
Egypt's public prosecutor ordered the arrest of Muslim Brotherhood leader Mohamed Badie and some other senior Islamists. He accuses them of inciting Monday's clash between Morsi supporters and the army which killed 51 people.
The military overthrew President Morsi last week after days of massive anti-government protests. Morsi opponents accuse him of betraying the 2011 revolution that forced long-time president Hosni Mubarak from office.
The U.S. State Department said this week that Morsi's government was not a democratic rule, but is refusing to take sides in the current political crisis. It says any transitional government must include all voices and parties.
The United States is still evaluating if Morsi's ouster was a military coup. If such a determination is made, U.S. law would require the government to suspend all non-humanitarian aid to Egypt.
Meanwhile, the U.S. says it is going ahead with a planned delivery of four F-16 fighter jets to Egypt. The planes are scheduled to arrive in August. They are part of a set of 20 planes Egypt is to receive this year under a deal approved in 2010.