The death of Reza Hoda Saber, a journalist and political activist, coincided with the second anniversary of the disputed re-election of President Mahmoud Ahmadinejad, which sparked protest rallies in 2009.
Opposition website Kaleme said Hoda Saber had begun a hunger strike after opposition activist and women's rights campaigner Haleh Sahabi died at the funeral of her father on 1 June after scuffles broke out with security forces. Tehran is a key backer of Syria and has dealt harshly with any internal dissent.