Iran's Foreign Ministry said a U.S, citizen, Michael White, had been arrested in the city of Mashhad, according to the Islamic Republic News Agency, confirming earlier reports.
The New York Times reported on Monday that White, a 46-year-old U.S. Navy veteran, was arrested while visiting Iran and had been held in jail since July on unspecified charges.
Iranian officials had not confirmed the arrest before Ministry spokesman Bahram Qassemi's statement, which did not specify when it took place.
The New York Times has quoted White's mother saying she learned three weeks ago that her son is alive and being held at an Iranian prison.
His arrest was first reported by an online news service by Iranian expatriates who interviewed a former Iranian prisoner who said he met White at Vakilabad Prison in the city of Mashhad in October.