British Foreign Secretary Boris Johnson in Tallinn, Estonia, September 7, 2017. REUTERS/Ints Kalnins/Files

LONDON: British Foreign Secretary Boris Johnson is set to visit Iran this weekend, where he is expected to raise the case of a British-Iranian woman held in a Tehran prison, The Guardian reported on Thursday.

Johnson will meet with his Iranian counterpart Javad Zarif and is also expected to hold talks on the Iranian nuclear deal, the report said.

It would be the first visit by a British foreign secretary to Iran since 2015 and only the third since 2003.

The Foreign Office refused to confirm the trip.

Nazanin Zaghari-Ratcliffe was sentenced to five years in prison in September 2016 for taking part in the mass anti-regime protests in 2009, which she denies.

She was working at the Thomson Reuters Foundation ? the media organisation's philanthropic arm ? at the time of her arrest.

She is due to face fresh charges in the court of "spreading propaganda" on December 10.

Thomson Reuters chief executive Monique Villa said recently that the new charges risked a further 16-year prison sentence and were "a mockery of justice".

Zaghari-Ratcliffe was arrested at Tehran airport on April 3, 2016, after visiting family. She was travelling with her daughter Gabriella, now three years old.

The case has become highly politicised, especially after a "slip of the tongue" by Johnson last month when he stated that Zaghari-Ratcliffe had been training journalists in Iran, which has been used by the Iranian authorities to help justify the new charges.