The official news agency of Iran's judiciary says a British-Iranian national has been sentenced to six years in prison on spying charges.

The report Sunday night by the Mizan news agency did not elaborate or identify the person sentenced.

However, there is no known case of a British-Iranian national being sentenced to six years in prison.

Britain's Foreign Office did not immediately respond to a request for comment late Sunday night.

Analysts and family members of dual nationals and others detained in Iran have suggested that hard-liners in the Islamic Republic's security agencies use the prisoners as bargaining chips for money or influence.

A U.N. panel in September described "an emerging pattern involving the arbitrary deprivation of liberty of dual nationals" in Iran, which Tehran denies.