The United Nations special rapporteur on freedom of assembly has called the Cambodian authorities’ continuous blockade of Freedom Park, the enforcement of which saw security guards attack journalists and supporters of opposition lawmaker-elect Mu Sochua on Monday, “deeply disturbing”.

“The authorities have no legal basis for using violence in response to a peaceful assembly. They also have no basis for banning peaceful assemblies,” Maina Kiai, the Kenyan lawyer who monitors the rights to freedom of peaceful assembly and association worldwide as a special envoy of the UN, said in an email on Wednesday.

Kiai said he had seen no information contradicting media and civil society reports that the gathering was “entirely peaceful, and there was no legitimate reason to halt it or to use force in response”.

Sochua has repeatedly tried to enter Freedom Park this month to draw attention to what she says is the critical state of freedom of expression in Cambodia. Despite the government’s lifting of a general ban on public assembly in February, the capital’s designated protest space has been kept off limits to demonstrators and gatherings with political undertones.

“The right to freedom of assembly is about preserving pluralism, and pluralism is essential in a democracy. We might not always agree with what a person or a group says, but we must defend their right to say it,” said Kiai, who paid an unofficial visit to Cambodia in February when the ban was in place.

“The overall atmosphere for civil discourse and space in Cambodia seems to have taken a sour turn in the months since I visited, particularly on the legislative front,” he

said, referring to proposed laws on NGOs, cybercrime and trade unions.

City Hall has characterised Monday’s violence as part of law enforcement and accused Sochua of incitement for political gain. On Tuesday, Sochua announced that she would take legal action against Daun Penh Deputy District Governor Sok Penh Vuth, who reportedly ordered security guards to attack the crowd on Monday.