Iran detains dual nationals on unknown charges

Iran's official judiciary news agency Mizan reported on Monday that the charges were announced by Tehran's prosecutor, Abbas Jafari Dowlatabadi.

The four, who have ties to Britain, Canada and the United States, all are believed to have been detained by hard-liners in Iran's paramilitary Revolutionary Guard in connection with separate cases over the past year.

According to Al Jazeera, family members and representatives of the four say they did nothing wrong and Dowlatabadi's statement did not elaborate on the charges.

He said another seven people faced charges related to the unrest that surrounded the country's disputed 2009 presidential election.

Iran does not recognise dual nationalities, meaning those detained cannot receive consular assistance.

In previous cases involving dual nationals, like the detention of Washington Post journalist Jason Rezaian, officials initially announced indictments had been handed down without providing specifics.

Those detained typically face trial in Iran's Revolutionary Court, a closed-door tribunal which handles cases involving alleged attempts to overthrow the government, Al Jazeera explains.

The hard-line crackdown since the nuclear accord has included the detention and sentencing of Iranian poets, filmmakers, artists and others.

Most recently, famed Iranian sculptor Parviz Tanavoli found himself banned from traveling abroad and had his passport seized.