The BBC on Friday urged Iran to end what it said was a mounting campaign of threats and intimidation against its journalists and their families at home and abroad.
The UK national broadcaster said staff from its Farsi language service have endured more than a decade of harassment and attacks, including asset freezes and arbitrary arrest of relatives.
Iran's campaign against the service started during the 2009 Iranian presidential election, when the regime tried to jam the channel’s satellite broadcasts.
In 2017, Iranian authorities launched a criminal investigation into 152 current and former journalists with BBC Persian – the Farsi language radio station and TV channel operated by the BBC – accusing them of conspiracy against national security and freezing their assets.
The BBC has previously said that one staff member received a doctored photo showing her mother covered in blood. Another death threat warned of a journalist being skinned alive.
In the past year, threats against BBC News Persian staff and journalists outside Iran have escalated, the broadcaster said.
These included death threats and “threats of extraterritorial harm” towards staff in London, leading to police involvement and protection, said the BBC.
The harassment of staff intensified when journalists covered the crackdown on mass anti-government protests in November 2019.
The campaign has extended to journalists from other organisations perceived to be critical of the regime, forced returns from overseas and imprisonment, the BBC said.
The UN has voiced concern about treatment of staff, saying the authorities in Tehran were prepared to go to illegal lengths to silence reporters.
The BBC's World Service operation is part-funded by Britain's Foreign Commonwealth and Development Office but is editorially independent of government.
Diplomatic relations between the two countries are strained over Tehran's nuclear ambitions and its detention of dual nationals, said to be linked to a historic unpaid debt from a military deal before the shah of Iran was deposed in 1979.
BBC World Service's lawyers Caoilfhionn Gallagher and Jennifer Robinson said Farsi service staff “receive threats of death and violence simply for doing their jobs".
“We call on the international community to take immediate, robust action to ensure Iran is held accountable, and BBC News Persian journalists can report without fear,” they said in an appeal to mark International Human Rights Day.
BBC News Persian has a weekly global audience of nearly 22 million people, including some 13 million in Iran, the corporation said.