With 10 alleged members of the “terrorist” Khmer National Liberation Front (KNLF) facing charges of treason, police yesterday threatened further arrests in Cambodia and abroad.

At a press conference yesterday morning, which was held in response to a spate of criticism from rights groups who claim that the arrests were unjustified, National Police spokesman Kirth Chantharith said the action was based on a “clear investigation” that had uncovered evidence, including KNLF flags, membership letters and leaflets calling for action to be taken against the government.

“The KNLF is an illegal organisation aiming to overthrow the government … [and it] came from the Khmer National Unity Front [KNUF], a terrorist group,” he said.

The KNUF, or Tiger Head Movement, was accused of attempting to bomb the Cambodia-Vietnamese Friendship Monument in 2007, and the Defence Ministry and state television station TV3 in 2009.

Rather than drop the charges, as rights groups have requested, Chantharith said that police would continue efforts to find and arrest KNLF members.

Following Thai coup leader and Prime Minister Prayuth Chan-ocha’s maiden visit to the Kingdom last week, Chantharith said Thailand would also crack down on the dissidents.

“What Prayuth has promised to Hun Sen is normal … [we] have to show commitment to helping each other,” he said. “We are determined not to allow groups of people based overseas to work against the government and against international law.”

KNLF leader Sam Serey, who founded the group in December 2012, could not be reached yesterday, but said last week that after months in Thailand, he had returned to Denmark.

But while Serey is no longer in Thailand, he has previously claimed that thousands of the group’s members live there, often while seeking asylum in other countries, hiding in the shadows to avoid persecution.

Phil Robertson, deputy director of Human Rights Watch’s Asia division, said he was concerned about the cooperation.

“Our understanding is there has been an agreement not to allow either side’s dissidents to seek refuge in the other country,” he said, explaining that members of the Thai pro-democracy “red shirt” movement in Cambodia could also be at risk. “Many of them [KNLF members] have refugee status from UNHCR [the United Nations High Commissioner for Refugees]; they should not be arrested.”

“The international community should be paying close attention that governments are going after people who have sought and gotten refugee status,” he added.

Chhem Vimean, whose father, Chhem Smak, was among those arrested last month, said that despite knowing of her father’s membership of the group, she believed it was not a “terrorist” organisation.

“He has never used any weapons to fight the government. The KNLF has policies based in Cambodian law, which is designed to allow people to express their rights,” she said.

Nay Vanda, of local rights group Adhoc, which is assisting families of those arrested, said many of the accused had no involvement with the KNLF.

ADDITIONAL REPORTING BY ALICE CUDDY