Sam Serey, president of Khmer National Liberation Front branded a terrorist organization by Prime Minister Hun Sen, was arrested by Thai authorities on Wednesday.
General Khieu Sopheak, spokesman for the Interior Ministry, said on Thursday that Cambodian officials have received information that Mr Serey was apprehended on Wednesday in Bangkok when he asked for a visa extension.
“Sam Serey was arrested yesterday at about 10 am or 11 am in Thailand,” Gen Sopheak said.
“He stays illegally in Thailand because of visa expiration,” he said.
Gen Sopheak said that Cambodian officials are preparing document to have Mr Serey extradited.
“We will ask Thai authority to send him to Cambodia because we have a court verdict,” he said.
Mr Serey was sentenced in absentia to nine years in prison for allegedly trying to topple the government in 2014.
He was granted asylum in Denmark after living as a refugee in Thailand for a number of years and has established a government-in-exile in Denmark.
Since 2014, about 20 KNLF members have been convicted after being found guilty of plotting to topple the government and inciting people to protest against the government. Each was sentenced to between one and ten years in jail.
A total of 18 KNLF members are currently behind bars in Phnom Penh.