Derrik Sweeney, Luke Gates and Gregory Porter, who attend the American University in Cairo, were arrested near Tahrir Square on Sunday.
The three were accused of throwing firebombs at security forces during recent violence. It's unclear when they will be released.
Meanwhile, there's an uneasy truce between demonstrators and police after five days of violent confrontation in the streets. It's unclear how long the truce will last.
Forty people were killed in the violence and hundreds of others were injured.
Demonstrators planned another protest later Thursday.