Former opposition leader Sam Rainsy has been summonsed from exile to answer a charge of “treason” over an alleged agreement he made with a pro-Montagnard activist.

Phnom Penh Municipal Court Deputy Prosecutor Sieng Sok issued a letter on Thursday to summon Rainsy as a “suspect” to appear in the municipal court for questioning on May 7.

A court document posted by police to Rainsy’s home, the former CNRP headquarters in Chak Angre Leu commune in Phnom Penh’s Meanchey district, stated Rainsy was called to clarify an agreement he signed with Kok Ksor in 2013 that authorities claim would have ceded land to the Degar, also known as Montagnards.

Rainsy, who has been in self-imposed exile since late 2015 to avoid jail time for a slew of politically motivated criminal charges, said he “couldn’t care less” about the summons.

“When it comes to politics, Cambodia’s subservient court has been already so much decried and ridiculed that any additional charge they levy against me becomes meaningless, not to say laughable,” he said in an email on Friday.

Montagnards is an umbrella term meaning “mountain people” that includes several ethnic minority groups stretching from Vietnam’s central highlands into northeastern Cambodia, including the Jarai. Hundreds of Vietnamese Montagnards fled to Cambodia from Vietnam in the past few years seeking asylum from persecution.

In 2013, Rainsy met with pro-Montagnard activist Kok Ksor, and, mostly quoting from the UN Declaration on the Rights of Indigenous People, he promised a degree of “autonomy” to the ethnic groups should his now-dissolved party win power.

Prime Minister Hun Sen and other government officials have interpreted that meeting as an agreement to cede four provinces to the Montagnards, which Rainsy has denied.

“This judicial farce only shows a fearful Hun Sen cowardly and desperately trying to further and further discard me from the electoral process,” Rainsy said. “But history shows that no tyrant has ever had the last word.”

The allegedly treasonous promise has been gaining traction as a talking point in a ruling party narrative that the opposition has colluded with foreigners. Deputy Prime Minister Men Sam An broached the topic in a speech to border police officers on Saturday in Koh Kong, likening Rainsy’s actions to the murderous Pol Pot regime.

“His actions are to weaken us, and [he] will brutally kill people, making our country falling into the three-year 20-day period of the Pol Pot regime, and we do not allow him to do that,” she said. She added that such an eventuality would be impossible under the leadership of Hun Sen, who would not even allow “10 centimetres” of land to be taken away from the country.

Hun Sen himself is a former member of the Pol Pot-led Khmer Rouge regime, defecting when he fled to Vietnam around halfway through the group’s rule over the country.