Former Islamist presidential candidate Abdel Moneim Abdel Fotouh was put on Egypt's terrorism list on Tuesday, state-rune MENA news agency reported.
He was arrested last week for maintaining contacts with the outlawed Muslim Brotherhood organisation, with whom the Egyptian interior ministry said he held secret meetings in London to stir unrest and instability in the country.
Egyptian president Abdel Fattah El Sisi, who is seeking a second term in a March 26-28 election is almost guaranteed to win. The vote has been criticised by international rights groups already uncomfortable with the government's restrictions on civil society.
Fourteen groups issued a statement saying the presidential election would be “neither free nor fair". However, the electoral commission has said that it will ensure the vote is fair and transparent.
Mr Abdel 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.
Read more: Egypt sentences 65 Muslim Brotherhood members to jail for incitement
Mr Abdel Fotouh's lawyer, Abdelrahman Haridy, said he had not yet been notified of the court's decision and that it was not yet clear if it included an asset freeze, reported Reuters. He said the designation could "easily" be appealed in court.
"It's clear that there is an insistence on tacking charges on to political figures in order to intimidate all politicians, even for just saying their opinions," Mr Haridy said.
Mr Abdel Fotouh along with 15 others were added to the list after an investigation by the state security prosecution found they had joined an outlawed organisation "aiming to harm the interests of the state", the MENA report said, without naming the organisation.
