Cecilia Sala left for Iran December 12 with a journalism visa and was scheduled to return a week later, but went dark a day before; Italian defense minister calls arrest 'unacceptable'

Iran has detained one of Italy’s best-known journalists, Cecilia Sala, in Tehran, raising fears that Iranian authorities might be holding her as leverage in their dealings with the West—an increasingly common tactic by authoritarian regimes.

Cecilia Sala, 29, was arrested on Dec. 19, but news of her detention only became public on Friday. The reason for the arrest of Ms. Sala, a well-known reporter, has not been made public.