Sept. 3 (UPI) -- Kem Sokha, leader of the Cambodian government's main opposition party, was arrested on Sunday morning and charged with treason.
In a statement released by the Cambodian government, officials accused Sokha, leader of the Cambodia National Rescue Party, of conspiring with foreign powers to undermine the current government.
"The Royal Government would like to inform the public that according to a video clip broadcasted by the Cambodian Broadcasting Network, based in Australia, and other evidences collected by the competent authority, it clearly proves the conspiracy between Kem Sokha and the accomplices with foreign power, which harms the Kingdom of Cambodia," the statement read.
While speaking to a group of garment workers on Sunday, Hun Sen, head of the Cambodian People's Party and prime minister since 1985, claimed Sokha had confessed to plotting regime change with the United States. Sen's son Hun Manith repeated the claim on Twitter.
Officials with the U.S. Embassy have denied the allegations.
Sokha's arrest was declared a "disastrous setback" by John Sifton, Asia advocacy director at Human Rights Watch.
Human rights activists say the latest arrest is part of an ongoing effort by Hun Sen to crack down on political dissent in the run up to next year's election. In recent weeks, the government has shut down several radio stations.
The English-language newspaper, The Cambodia Daily, announced plans to cease operations later this week. The paper said it is unable to pay a $6.3 million tax bill the government claims the news outfit owes.
The Cambodia Daily will publish its last headlines on Monday, "as a result of extra-legal threats by the government," according to a statement released by the paper on Sunday.
The paper and its publisher say the tax bill is simply an attempt quash free speech and political dissent.
"For 33 years, Hun Sen has used violence, threats, corruption and bogus legal charges to stay in power, and in the last year has been intensifying his attacks on civil society and the political opposition," Sifton said in a statement.
Steven Butler, Asia program director for the Committee to Project Journalists, told NPR the recent events in Cambodia are part of a growing antagonism toward a free press throughout Southeast Asia.
"I know it's absolutely true that press freedom has come under pressure in many countries," Butler said.