Iran's state-run news agency is reporting that an Iranian-British woman held there faces charges accusing her of trying to cause a "soft toppling" of the Islamic Republic's government.

IRNA's report on Wednesday marks the first official acknowledgment of the detention of Nazanin Zaghari-Ratcliffe, who works for the Thomson Reuters Foundation, the charitable arm of the news agency.

IRNA says Zaghari-Ratcliffe was arrested April 3 at Tehran's Imam Khomeini International Airport and later transferred to a prison in the country's Kerman province.

A call to the Thomson Reuters Foundation in London was not immediately answered on Wednesday.

Zaghari-Ratcliffe joins a growing number of dual Iranian citizens detained in the wake of the country's nuclear deal with world powers.

Iran long has viewed Britain with the same suspicion as the United States.