The weekly routine of “Black Monday” arrests continued yesterday with four activists detained for eight hours for protesting “without permission” against the imprisonment of four human rights workers and an election official on widely criticised charges.

Chray Nim, from land rights group SOS, said she was arrested at about 10:30am with Ngov Nary and Yim Srim, of the Borei Keila community, and former Boeung Kak resident Im Srey Touch by district police while the group was walking to SOS’s offices in Phnom Penh’s Por Sen Chey district.

Nim said the authorities told the activists, who were dressed in black and carrying a banner, they were being arrested for protesting without permission and affecting “public order”.

“The authorities warned us if we do it next week, they will send us to prison,” Nim said.

Phnom Penh Deputy Governor Khuong Sreng has previously said the municipality would move to prevent threats to the country’s stability.

Meanwhile, prominent Boeung Kak land activist Tep Vanny called on NGOs to step up and support the campaign, which seeks the release of four Adhoc staffers and an election official imprisoned over the Kem Sokha “sex scandal”.

Though many groups showed up for the first few protests in May, the following weeks have seen numbers dwindle, with mostly a core group of land dispute activists still participating. “I insist that civil society organisations lead and stand up all together, so that the community is not acting alone,” Vanny said.

Licadho senior technical coordinator Um Sam Ath said that many people still dressed in black to support the movement, despite not taking to the streets.