The Egyptian police released about 150 demonstrators detained during protests over the past two days.
The move was likely an attempt to calm the thousands who continue protesting across the nation.
A security source said state prosecutors started investigating other demonstrators in detention.
Security sources said at least 500 people were arrested nationwide after Tuesday's protests, whereas human rights groups estimated about 1200 people have been detained.
Security sources confirmed on Wednesday that authorities would not allow further protests.