British-Iranian woman imprisoned in Tehran temporarily released

The release is initially for three days, the statement said, but Zaghari-Ratcliffe's lawyer is hopeful this can be extended.

"This was a very happy surprise after a number of false dawns recently, which had been increasingly unsettling," the campaign group said.

She is currently in Damavand, east of Tehran, with her family.

Zaghari-Ratcliffe has been serving a five-year sentence for allegedly spying against the Iranian regime. Her employer, the Thomson Reuters Foundation, disputes the allegations.

In May, Iranian media reported that she was due to face a new trial for "security-related" charges.

This is a developing story -- more to come