Journalists at the Freedom and Justice (al-Hurriya wa al-Adala) newspaper, which belongs to the Muslim Brotherhood, have condemned its ban and declared a sit-in at the Journalists Syndicate until its publication resumes.
Earlier on Thursday, Egypt banned the newspaper and halted its publication.
"It seems that someone has decided there is no room for a counter voice amid the ongoing media chaos," the journalists said in a statement on Facebook.
This is a grave violation of the freedom of expression guaranteed by all laws and charters of the world, the statement said.
The newspaper urged the Journalists Syndicate to take a stand on these oppressive procedures against what it called an important Egyptian newspaper.
It also called on human rights and freedom-supporting organisations to take a clear position on this attack on rights and freedoms.
The daily newspaper, named after the Brotherhood's political party, first appeared in October 2011.