Egyptian authorities have detained more than 1,100 people since the weekend when protests were held in several cities calling on coup leader Abdel Fattah el-Sissi to quit, human rights monitors said Wednesday.
Defying a ban on protesting without a permit, hundreds took to the streets in Cairo and other cities on Friday in response to calls for protests against alleged government corruption. The protests continued in the Red Sea city of Suez on Saturday.
Gamal Eid, head of the Arab Network for Human Rights Information, said his own group and two others -- the Egyptian Center for Economic and Social Rights and the Egyptian Commission for Rights and Freedoms -- had jointly documented more than 1,100 arrests.
The interior ministry could not immediately be reached for comment.
Hazem Hosny, a former spokesman for the short-lived 2018 presidential campaign of ex-military chief of staff Sami Anan, was detained on Tuesday evening, said Mustapha Kamel Al Sayyid, a fellow professor at Cairo University, citing Hosny's family.
Sayyid also said Hassan Nafaa, a prominent writer who also teaches at Cairo University, has been missing since 1500 GMT on Tuesday, citing Nafaa's family.
El-Sissi came to power after leading the overthrow of the Muslim Brotherhood's Mohamed Morsi, Egypt's first democratically elected leader, following mass protests against him in 2013.
Protests in Egypt have been rare under el-Sissi, who has overseen a broad crackdown on dissent that rights activists say is the most severe in the country's modern history.
El-Sissi's supporters say tough measures were necessary to stabilize Egypt after the turmoil that followed the 2011 uprising that toppled former strongman Hosni Mubarak.
The protests have rattled financial markets, with the Egyptian stock market's main index falling nearly 11% in trading between Sunday and Tuesday.
On Wednesday morning, the Arabic hashtag "El-Sissi is not my president" was trending with more than 40,000 tweets. Several Twitter hashtags have been used to rally support for the protests, while pro-El-Sissi hashtags have also appeared.
The protests took place after a former civilian contractor for the military, Mohamed Ali, posted a series of videos accusing El-Sissi and the military of corruption. El-Sissi dismissed the allegations as "lies and slander."
Ali has called for mass protests on Friday.