A Cambodian court has charged four environmental activists with insulting the king and plotting against the government, an official said Monday, after three of them were arrested for documenting waste run-off into a river.
Use of royal defamation laws in Cambodia is a relatively new phenomenon, with the legislation only enacted in 2018.
The three activists -- Sun Ratha, Ly Chandaravuth and Yim Leanghy of advocacy group Mother Nature -- were arrested Wednesday for documenting the draining of waste into Phnom Penh's Tonle Sap river.
Over the weekend they were "charged with conspiracy to plot and for insulting the king", Plang Sophal, a spokesman for Phnom Penh Municipal Court, told AFP in a text message Monday.
Also charged was Mother Nature's co-founder, Alejandro Gonzalez-Davidson, a Spanish environmentalist who was deported from Cambodia in 2015 after he criticised the government's plans for a controversial dam.
Sophal did not elaborate on why the activists were hit with those particular charges.
While Cambodia has a constitutional monarch, King Norodom Sihamoni, it has long been ruled by its strongman premier Hun Sen, Asia's longest-serving leader.
When the lese majeste laws were enacted in 2018, they triggered alarm from rights groups who warned they could be wielded to target dissent.
If sentenced, the Mother Nature activists face a maximum penalty of five years in prison for insulting the king, as well as 10 years behind bars for the conspiracy charge.
- 'A public service, not terrorism' -
The US ambassador to Cambodia, W. Patrick Murphy, said he was "very troubled" to hear about the arrests.
"Documenting pollution is a public service, not terrorism," Murphy wrote in a tweet on Monday evening.
"We urge authorities to be responsive to its citizens, not to silence them."
Last week the US embassy condemned the "worsening" situation in Cambodia and announced it was redirecting millions in funds from government entities to local NGOs.
Mother Nature has faced a raft of legal troubles from Cambodian authorities.
Last month, three environmental campaigners affiliated with the group were sentenced to between 18 and 20 months in prison for organising a peaceful march to protest against a massive lake in the capital being filled with sand.
The tussle over Cambodia's environment and resources has long been a contentious issue in the kingdom, with environmentalists threatened, arrested and even killed in the past decade.