Iranian authorities claimed in January that 26-year-old Matej Valuch was involved in Central Intelligence Agency activities in Iran.
Foreign Minister Miroslav Lajcak said Friday that Valuch was released after "difficult and complicated" bilateral negotiations. Lajcak gave no details.
Valuch, who was standing next to the minister at a news conference, denied he worked for the U.S. intelligence, saying "I am not a spy."
He declined to take questions. Lajcak said Valuch would not talk about his Iranian experience in the future.
In a documentary broadcast in Iran, Valuch said he was recruited by a CIA agent and ran a job recruitment agency in Tehran as a front.