Egypt's prosecutor-general on Tuesday issued a gag order on a police raid on the press syndicate which resulted in the arrest of two journalists.
On Sunday, police broke into the Journalists' Syndicate in central Cairo, arresting two journalists on charges of inciting protests and plotting to overthrow the ruling regime.
The raid has, however, provoked a firestorm from journalists, who staged a sit-in amid calls for sacking the interior minister.
In a statement, the public prosecutor's office said the raid was meant to carry out an arrest warrant on the two journalists.
The prosecution said that a gag order was issued into the case until investigation of the arrests is completed.
Earlier Tuesday, the Press Syndicate decided to lower its flag and replace it with black banners to protest the police raid, in a move that coincided with World Press Freedom Day.
The European Union had warned Egypt on Monday over the storming of the syndicate's building a day earlier. Undercover police officers detained two journalists who had been holding a sit-in in solidarity with detained colleagues.
The EU described the situation as a "worrying development, and continues a trend of restricting space for civil society and the freedom of expression".