President Donald Trump has said the US will take "very strong action" against Iran if it executes protesters, as rights groups say more than 2,400 anti-government demonstrators have been killed in a violent crackdown by Iranian authorities.
Relatives of 26-year-old Erfan Soltani, who was detained last week, told BBC Persian he was due to be executed on Wednesday. It is unclear whether this has taken place.
A representative from the Hengaw Organization for Human Rights also told the BBC that they had "never witnessed a case move so quickly".
Speaking to the BBC's US partner CBS News, Trump said of potential executions: "If they hang them, you're going to see some things... We will take very strong action if they do such a thing."
