Iran has executed a once-exiled journalist Rouhollah Zam over his online work that helped drive nationwide economic protests in 2017. Iranian state television and the state-run Irna news agency said Zam was hanged early Saturday morning. In June, a Tehran court sentenced Zam to death, saying he had been convicted of “corruption on earth”, a charge often used in cases involving espionage or attempts to overthrow Iran’s government. Iran's Supreme Court upheld his death sentence on Tuesday. The official Irna news agency said Zam was convicted of espionage for France and an unnamed country in the region, co-operating with the "hostile government of America", acting against "the country's security," insulting the "sanctity of Islam" and instigating violence during the 2017 protests. Zam fled Iran after the 2009 'Green Movement' protests over the re-election of president Mahmoud Ahmadinejad and was granted asylum in France. He was arrested in Iran under unknown circumstances in October last year. The French Foreign Ministry said he had left France on October 11 and that it had no information about his arrest. Iran's Islamic Revolutionary Guard Corps said it ran a “meticulous intelligence operation” to deceive foreign intelligence services and lure Zam back into the country for prosecution. Reporters Without Borders said Zam was kidnapped and forcibly returned to Iran. The Paris-based media watchdog said it was "outraged" by Zam's execution, describing it as a "new crime of Iranian justice". It also accused Iranian supreme leader Ayatollah Ali Khamenei of being the mastermind of Zam's killing. After fleeing Iran, Zam set up the Amadnews website and a channel on the messaging app Telegram that spread the timings of the 2017 protests and embarrassing information about figures in Iran’s Shiite theocracy. The demonstrations in December 2017 and January 2018, sparked by the rising cost of food, posed the biggest challenge to Iran's regime since the 2009 protests and set the stage for similar mass unrest that broke out in November last year after the government raised fuel prices. Telegram suspended Zam's Amadnews feed in 2018 for allegedly inciting violence but it later reappeared under another name. Zam is the son of Shiite cleric Mohammad Ali Zam, a reformist who once served in a government policy position in the early 1980s. The cleric wrote a letter published by Iranian media in July 2017 in which he said he did not support his son's reporting on Amadnews. Iran aired a series of a televised confessions by Zam earlier this year. During an interview in July, Zam said he had lost about 30 kilograms since his arrest. He said that following the arrest he was able to meet his father after nine years and his mother and sister after some six years. Zam is one of several people to have been put on death row over participation or links to protests that rocked Iran between 2017 and 2019. Navid Afkari, a 27-year-old wrestler, was executed at a prison in the southern city of Shiraz in September. The judiciary said he had been found guilty of "voluntary homicide" for stabbing to death a government employee in August 2018. Shiraz and several other urban centres across Iran had been the scene of anti-government protests and demonstrations at the time over economic and social hardship. Three young men were also sentenced to death over links to the 2019 protests, but Iran's supreme court said last week that it would retry them after a request by their lawyers. Their sentences were initially upheld by a tribunal over evidence the judiciary said was found on their phones of them setting fire to banks, buses and public buildings during protests. Amnesty International said Iran executed at least 251 people last year, the world's second highest toll after China.