Egypt has detained a Turkish citizen on suspicion of spying and collusion with the Muslim Brotherhood, the state news agency MENA said on Saturday.
The arrest could be a new source of tension between Ankara and Cairo whose relations have all but broken down since Mohamed Mursi, whose Muslim Brotherhood has close ties with Turkey's ruling AK Party, was ousted from the Egyptian presidency in July.
Rasit Oguz, a 46-year-old Turk, was arrested in the city of Ismailia northeast of Cairo on August 28 while taking photographs of military establishments, security sources said.
MENA said delegates from the Turkish mission in Cairo were following up on his case and had visited him in detention.
Turkey has emerged as one of the fiercest international critics of Mursi's removal, calling it an "unacceptable coup".
It recalled its ambassador in August after a violent crackdown on Mursi's supporters. He returned to Cairo this month but Egypt said it would not reciprocate until Turkey stopped its "interference".