British-Iranian charity worker Nazanin Zaghari-Ratcliffe left an Iranian prison for a three-day furlough Thursday — a breakthrough in the case that her family hopes will lead to permanent freedom.

British Foreign Secretary Jeremy Hunt welcomed her temporary release and called on Iranian authorities "to capitalize on the goodwill from today's announcement by going the whole way and releasing Nazanin and allowing her to go back to her family and come back to the UK."

Hunt told reporters at U.N. headquarters in New York that she "is innocent" and "every day that she is in prison is a reminder to the whole world of a gross injustice." Iranian authorities accuse her of plotting against the government.

Richard Ratcliffe said his wife was released from Evin prison and has been reunited in Iran with her 4-year-old daughter Gabriella. The Free Nazanin campaign released images showing the beaming mother hugging her child and clutching a bouquet of roses.

"Gabriella had picked some flowers from the family garden, and was waiting to present them — the tradition she has seen for families waiting outside Evin prison. Gabriella has promised to show her the garden, and also her dolls house," Richard Ratcliffe said. "She (Nazanin) was very happy on the phone, though confessed to having cried lots, particularly when seeing her grandmother, and to being still overwhelmed."

Nazanin Zaghari-Ratcliffe
Family handout photograph showing British-Iranian aid worker Nazanin Zaghari-Ratcliffe reunited with her daughter Gabriella after her temporary release from an Iranian jail, in Tehran, Iran August 23, 2018.

Zaghari-Ratcliffe was arrested during a holiday with her toddler daughter in April 2016. Her family says she was in Iran to visit family, denying that she was plotting against its government.

A former employee of the BBC World Service Trust, Zaghari-Ratcliffe worked for the Thomson Reuters Foundation, the charitable arm of the news agency.

Former British Foreign Secretary Boris Johnson was heavily criticized last year after he claimed Zaghari-Ratcliffe was "teaching people journalism" when she was arrested. Although Johnson later corrected himself, Iranian state television highlighted his comments as justification for imprisoning her.

In an unusual move, Iran's ambassador to London, Hamid Baeidinejad, posted a tweet on the release, offering a link to the image of mother and child.

"She immediately joined her four-year-old daughter, Gabriella who welcomed her mom with flowers," he said. "Lovely picture."

As recently as May, Zaghari-Ratcliffe learned that she faced a new charge of "spreading propaganda against the regime," her husband said. It remains unclear if that threatened charge remains in play.

Zaghari-Ratcliffe's release also comes as London is considering repaying Tehran about 400 million British pounds from a pre-1979 arms deal.

Richard Ratcliffe thanked Foreign Secretary Jeremy Hunt, who recently took over from Johnson as foreign secretary.

"Really good news that Nazanin has been released on furlough, credit to tireless campaigning by husband Richard and her friends," Hunt tweeted . "But being in prison AT ALL is gross injustice and she must be PERMANENTLY released for which every effort will continue."