“We are deeply concerned by credible threats to the lives and safety of 45 Iran International journalists and staff and 315 of their family members,” the experts said in a joint statement.
The statement comes after Iran International filed an urgent appeal earlier this month with the experts urging them to take action against Iran over serious risks to the lives and safety of their journalists worldwide and relatives inside Iran.
UN experts said several UK-based journalists have required police protection, with some forced to move into safe houses or relocate abroad.
"Reports suggest that journalists have been followed, had tracking tags attached to their cars, and their cars repeatedly broken into. Women journalists have faced threats of death and sexual violence on social media and instant messaging services, some receiving hundreds of messages a day."
The experts which included UN Special Rapporteur on the situation of human rights in Iran, Mai Sato, said the latest phase of repression had increasingly targeted family members in Iran, who have been interrogated, placed under surveillance, and threatened with arrest or death.
Interrogators allegedly demanded that relatives pressure journalists to quit Iran International or serve as informants, particularly concerning alleged ties to Israel, the statement said.