Aboul Fotouh, a former hard-liner who leads the Strong Egypt party, was arrested last week a day after returning from London, where he had given interviews sharply critical of President Abdel Fattah El-Sisi ahead of next month’s presidential election.
The Interior Ministry said at the time that Aboul Fotouh held secret meetings with leaders of the Muslim Brotherhood while in London to implement a plot to stir unrest and instability in the country, accusations he denied.
Aboul Fotouh was among the first of several high-profile Egyptians to call last month for a boycott of the election.
Individuals added to the terrorism list are generally subjected to an asset freeze and a travel ban and are permitted 60 days to appeal the decision.
Aboul Fotouh’s lawyer, Abdelrahman Haridy, told Reuters he had not yet been notified of the court’s decision but that the designation could “easily” be appealed in court.
Aboul Fotouh along with 15 others were added to the list after an investigation by the state security prosecution found they had joined an outlawed organization “aiming to harm the interests of the state,” state news agency MENA reported.
In an interview with Al Jazeera Mubasher, a Qatar-based channel banned in Egypt, Aboul Fotouh last week criticized El-Sisi in unusually pointed terms.
The 67-year-old physician quit the Muslim Brotherhood in 2011 after disagreements over the role of religion in politics and founded the more centrist Strong Egypt party.
He mounted an independent bid for the presidency in 2012 and took nearly 18 percent of the vote in the first round of elections.
Egypt banned the Brotherhood in 2013 after President Mohamed Mursi was ousted by the military following mass protests. The group has since been declared a terrorist organization by the government.