Banteay Meanchey police officials detained and later released human and environmental rights activist Hun Vannak on Monday, as security forces were deployed for a planned protest by market vendors in Poipet town.

Poipet residents, most of whom are market vendors in Rong Kleu Market in Thailand across the border, planned to demonstrate on Monday morning requesting that the border to be reopened to resume trade in the market. The Thai border has been closed since March to prevent the spread of the novel coronavirus.

Hun Vannak, who was at the protest as an independent observer, was documenting the planned demonstration, especially the heavy security presence that had been deployed by provincial authorities. While taking photographs and videos of the security presence, Hun Vannak said he was arrested and taken to a site near the train station for questioning.

�If there is violence against the people, then that would be a human rights violation,� said Hun Vannak, who is also part of a newly-formed youth movement called Khmer Thavareak. �And as a human rights activist, I need to monitor that.�

Hun Vannak told VOA Khmer that he was accused of collecting information for the opposition party, a reference to the dissolved Cambodia National Rescue Party. He was forced to delete all the photos and videos he filmed on Monday, but he refused to sign an agreement with the police nor did he speak during his questioning, which was filmed by the police.

The youth activist previously worked for environmental protection NGO Mother Nature, and was imprisoned for 18 months in early 2018 for his activism against sand dredging in Koh Kong province.

Seth Los, deputy chief for the Banteay Meanchey provincial police, said authorities only wanted to question Hun Vannak and had not arrested him. He added that they educated Hun Vannak and released him after asking him not to indulge in any �illegal activities.�

�We invited him to sit with us to ask him where he come from and what his work is,� said Seth Los. �After we got the answers, the deputy prosecutor educated him and allowed him to go back to his house.�

Asked about the heavy security presence in Poipet, Seth Los said it was in response to the planned demonstration, refusing to provide additional details.

Din Puthy, head of the Cambodia Informal Economy Reinforced Association which helps informal workers in the border town, said the protest on Monday was canceled because of the heavy security presence.

The civil society member said market vendors and transportation workers were hurting financially because of the border closure and authorities needed to open the checkpoint to allow vendors to trade.

�So, if we cannot earn, we don't have money to spend,� Din Puthy said. �They have to spend on their bank loan, children�s school fees, food, electricity, and everything. That is why they worry that they might have to go hungry.�

VOA Khmer could not reach Banteay Meanchey Governor Um Reatrey for comment on Monday.

Local publication VOD English reported last week that authorities had deployed security forces across the border town after a request for the protest was rejected by the province, especially a heavy presence of security personnel at Din Puthy�s residence.

Sum Chankea, rights civil society group ADHOC�s Banteay Meanchey monitor, said preventing residents from protesting and the detention of Hun Vannak was a serious violation of human rights.

"It is the violation of liberties and the freedom of expression, including dissemination of information,� he said.