By Ramin Mostaghim and Ivana Kottasová, CNN

Dissident Iranian journalist Rouhollah Zam was hanged in Iran on Saturday morning, according to state television IRIB.

Zam was found guilty of "corruption on earth," a charge that does not specify a crime​ but is sometimes used by the Iranian government for alleged attempts to overthrow it.

Zam ran the ​online opposition news site Amad News, which was accused by Tehran of inciting violence during deadly protests in 2017 and 2018, the semi-official Tasnim news agency reported in 2019.

Reporters Without Borders said Saturday it was "outraged at this new crime of Iranian justice." The group had been campaigning for Zam's death sentence to be overturned, alleging he was "illegally kidnapped and arrested" and "tried in a grossly unfair manner."

Zam had been living in exile in France when he was arrested by Iranian authorities in October 2019. The circumstances of how and where he was detained remain unclear. The journalist left France on October 11, according to the French foreign ministry. Three days later, Iran's ​Islamic Revolutionary Guard Corps released a statement saying it had detained him.

Following his arrest, Iranian authorities released a video of Zam in a car, wearing black-out goggles. The video also shows him sitting in front of a camera, making an "apology" for his actions.

He was found guilty and sentenced to death in June.

The European Union condemned the execution, calling on Iran to "refrain from any future executions and to pursue a consistent policy towards the abolition of the death penalty."

"It is also imperative for the Iranian authorities to uphold the due process rights of accused individuals and to cease the practice of using televised confessions to establish and promote their guilt," the spokesperson for the EU's External Action Service said in a statement on Saturday. "The EU believes that the death penalty is a cruel and inhumane punishment, which fails to act as a deterrent to crime and represents an unacceptable denial of human dignity and integrity," the statement added.

Iran had accused Zam of working with US, French and Israeli intelligence that provided him with "overt and covert" protection, according to ​Iran's semi-official Fars ​news agency.

Reporters Without Borders says Iran has been one of the world's most repressive countries for journalists for 40 years. The group says at least 860 journalists and citizen-journalists have been imprisoned or executed in Iran since 1979.

CNN's Schams Elwazer contributed reporting.