Egypt's Prosecutor-General Nabil Sadek ordered on Wednesday 29 suspects detained for 15 days pending investigation into charges of engaging in espionage with Turkey, state-run news agency MENA reported.
The 29 suspects, along with others who are fugitives abroad, are accused of joining a terrorist organisation, circumventing the country’s phone networks for international communication, money laundering, and illegal currency trading, according to a statement by the prosecutor-general.
The statement did not state when the defendants were arrested.
According to National Security investigations, the defendants formed a network with fugitive members of the Muslim Brotherhood abroad to monitor and record phone calls of Egyptian citizens to gauge their views on the situation in the country.
Egyptian intelligence agencies revealed a plot between Turkish intelligence and members of the international Muslim Brotherhood to take over power in Egypt by destabilising state institutions.
The State Security prosecution said it would continue to release statements on the case while maintaining confidentiality with regards to information that could harm the country's national security.
Relations between Turkey and Egypt have been strained since the 2013 ouster of Egypt’s Islamist president Mohamed Morsi, a close ally of Turkish President Recep Tayyip Erdogan's AKP government.
Erdogan has repeatedly slammed the Egyptian government over Morsi's removal.
Cairo has repeatedly accused Ankara of interference in its domestic affairs and supporting Islamist terrorists who carry out attacks in Egypt.
Turkey has been providing a safe haven for leading members of the Brotherhood, which has been banned and designated as terrorist in Egypt.
Ankara also allows broadcasts from within Turkey of TV stations run by sympathisers of the Brotherhood who criticise the government of President Abdel-Fattah El-Sisi.
Political relations between the two countries are currently suspended, though economic ties are still active.