Hossein Shanbehzadeh, an Iranian literary editor and online activist, has been detained for unknown reasons in the northwestern city of Ardabil.
Family sources said on June 4 that Shanbehzadeh confirmed his detention in a phone call.
The case highlights ongoing tensions in Iran regarding freedom of expression, particularly on social media, and adds to the growing concern over the treatment of intellectuals and activists in the country.
Shanbehzadeh, known for his biting criticism of the authorities, said he wasn't informed of the reason for his detention, but it comes after he posted a simple period in a social media response to a tweet by Supreme Leader Ayatollah Ali Khamenei posing with the Iranian national volleyball team.
The response went viral, garnering more likes than the original tweet by Khamenei.
Soon after, Shanbehzadeh's account on X (previously known as Twitter) was inaccessible, with his last post on it authored by someone else, according to his brother Abbas.
It's not the first time Shanbehzadeh has faced legal issues over his online activities.
In 2019, he was sentenced to prison on charges of "insulting the sanctities and the leader of the Islamic republic" for critical comments about Iran's leadership.
His professional work includes editing prominent literary works such as Naguib Mahfouz's Heritage And Life With Him, in addition to being a well-known social media activist.