An outspoken labor rights advocate who recently called for the Islamic Republic's Supreme Leader Ayatollah Ali Khamenei to step down has been arrested at his home.

The intelligence agents stormed Esmaeil Ahmadi Ragheb's (nicknamed Zartosht) house in the city of Shahriar, 39 kilometers (approximately 24 miles) west of Tehran, breaking down the door on Tuesday, August 27, and took him away to an unknown detention center.

Ahmadi Ragheb recently sacked as a firefighter, is a signatory to an open letter published in mid-June calling on Khamenei to resign while also demanding essential changes in Iran's Constitutional Law.

At least seven out of the fourteen signatories to the bold letter have been detained, so far.

Meanwhile, in early August, a group of fourteen female activists also issued a similar statement demanding equal rights for women and asking for Khamenei to step down and pave the way for a new constitution.

Seven out of the fourteen signatories to this letter, including have also been arrested, so far.

Ayatollah Khamenei has in the past stated publicly that people are free to criticize him, but often the slightest criticism or protest leads to arrests and in many cases jail terms.