The husband of an Iranian-British charity worker who has been held without charge in Iran since April on Friday called for her release at a rally outside the Iranian embassy in London.

Nazanin Zaghari-Ratcliffe, 37, was arrested at Tehran airport on April 3 as she prepared to return to Britain with the couple's daughter Gabriella after visiting family in Iran, Richard Ratcliffe told AFP.

Gabriella, who turns two on Saturday, was born in Britain and has a British passport, which was confiscated by the Iranian authorities, leaving her stranded with her grandparents in Iran.

His wife, who spent the first 45 days in solitary confinement, was later transferred to Karman prison, 1,000 kilometres (621 miles) from Tehran, although Ratcliffe said the family had not received "any news since Sunday".

Britain's Foreign Office has said it has raised the case "repeatedly and at the highest levels" and will continue to do so at "every available opportunity".

Middle East Minister, Tobias Ellwood, had met the family to reassure them that diplomats would "continue to do all we can on this case", a ministry spokesman told AFP.

Zaghari-Ratcliffe works for the Thomson Reuters Foundation, a charity organisation coordinating training programmes for journalists around the world."She has nothing to do with Iran in her work and the foundation doesn't work with Iran anyway, so we have no idea why she has been detained for more than two months, first in isolation and then in a common cell," foundation CEO Monique Villa told AFP.

"Now we don't know because she seems to have disappeared from where she was."

Ratcliffe led the celebrations for his daughter's birthday, talking to her on Skype, leading a mass singalong of "Happy Birthday" and placing a giant card and balloons on the steps of the embassy. 

The case of 76-year-old Iranian-British man Kamal Foroughi, was also brought up at the rally by his son Kamran.

Foroughi was arrested in 2011 and sentenced to eight years in prison on spying charges, having spent two years in detention without charge.

Source :AFP