Iran has arrested a British citizen on suspicion of having links to UK spy agencies, the country's state-run IRNA news agency has announced.
It said the unnamed suspect, who also had Iranian nationality, was "active in the economic field" and had been held last week.
A Foreign Office spokesman said: "We are seeking information following the reported detention of a dual Iranian-British national in Iran."
The latest arrest follows the detention of at least six other dual nationals for alleged security related offences since the signing last year of Iran's nuclear agreement with leading world powers.
The detainees include British-Iranian charity worker Nazanin Zaghari-Ratcliffe, who was arrested at Tehran's airport in April as she tried to return to the UK after a holiday with her two-year-old daughter, Gabriella.
Iran does not recognise dual nationalities, meaning those detained cannot receive consular assistance.