Iran on Wednesday executed a man convicted of espionage for Israel and involvement in the killing of a Revolutionary Guard but activists said he was sentenced to death after an unfair trial and a confession obtained by torture.

Mohsen Langarneshin, reportedly aged 34, was hanged at dawn at Ghezelhesar prison in Karaj outside Tehran, several rights groups said.

His mother and father held a vigil outside the jail during the night, pleading for his life to be spared, images on social media showed.