American independent non-profit organization the Committee to Protect Journalists (CPJ) has urged Iranian authorities to stop “arbitrarily” locking up journalists.

“Iranian authorities must understand that they can’t hide the country’s difficult realities and problems by silencing and jailing journalists,” Justin Shilad, CPJ’s Middle East and North Africa senior researcher, said Wednesday in New York.

The international press rights group called for the unconditional release of freelance reporter Arash Ghaleh-Golab, arrested at a mourning ceremony for victims of a collapsed building in the south-western city of Abadan, which killed at least 37 and led to protests in south-west Iran and elsewhere.

The CPJ cited a “source familiar with the case” that when Ghaleh-Golab was arrested “officers hit the journalist with their fists and kicked him.” The group said Ghaleh-Golab was being detained without charge at an undisclosed location and not allowed to contact his family.

The Iranian Writers Association has also expressed concern about Ghaleh-Golab and other detainees of the protests in Abadan and other cities in Khuzestan province. Security measures, including restrictions on the Internet, had made the situation of journalists and other detainees “very worrying,” the association said.