Cambodia has begun a mass trial of politicians and activists, in what human rights groups described as an attempt by the country’s leader to wipe out his remaining opposition while the world is focused on fighting Covid-19.

At least 136 people, nearly all affiliated with the banned opposition Cambodia National Rescue party, face charges of treason, incitement and other crimes, according to the Asean Parliamentarians for Human Rights, a campaign group of south-east Asian MPs.

Cambodian authorities outlawed the party in 2017 after putting Kem Sokha, its president, on trial for treason.

After the party was banned, Hun Sen, who has been Cambodia’s prime minister since 1985, won all the seats in parliament in the last general election in 2018.

“This [trial] is a total weaponisation of the justice system by Mr Hun Sen in order to continue to keep his power,” Mu Sochua, the party’s vice-president, told the Financial Times. “It’s also because he’s preparing the terrain for local elections in 2022 and general elections in 2023.”

The 68-year-old Cambodian leader, an ally of Chinese president Xi Jinping, is grooming his son Hun Manet, 43, as a potential successor. Last year his government adopted a state of emergency law that gave Hun Sen sweeping censorship, surveillance and other powers, which the prime minister said he needed to fight Covid-19.

“Prime Minister Hun Sen took advantage of the global pandemic to step up his repression of critics and adopt more draconian laws,” said Phil Robertson, deputy Asia director for Human Rights Watch.

Cambodia’s government spokesman Phay Siphan did not respond to a request from the FT for comment.

The case opened in a Phnom Penh municipal court in November, but a judge postponed the proceedings after splitting the case into two groups and scheduling hearings for January and March.

Amnesty International called the cases brought against opposition figures “cynical show trials”, and described them as part of “a relentless campaign of persecution against Cambodia’s political opposition and other dissenting voices”.

According to APHR, the mass trial had its origins in a crackdown on political activists that preceded an attempt by Sam Rainsy, an exiled opposition leader, to return home in 2019, which was thwarted after neighbouring Thailand refused him passage.

About 15 CNRP figures charged in the case are now in exile, according to Mu Sochua who is in the US. She said she wanted to return to Phnom Penh to face charges, but had been refused entry by Cambodian consular authorities.

In response to the Cambodian regime’s repression, the US has imposed sanctions on some top officials and their companies under the Global Magnitsky Act. The EU last year revoked trade preferences worth about €1bn enjoyed by Cambodian exporters.

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