As opposition leaders marked the anniversary of the 1997 coup on the weekend, the royalist Funcinpec party lashed out, criticising the Cambodia National Rescue Party for exploiting a tragedy for political benefit.

Funcinpec secretary-general Nhek Bun Chhay, who commanded the royalist forces of Prince Norodom Ranariddh against Cambodian People’s Party troops led by Hun Sen, said the event was held to “seek political gain”.

“That’s why we hold this ceremony during Pchum Ben and Khmer New Year, because [the spirit] of individuals who died will come to find their relatives [at that time of year],” he said. “Some [politicians] have said we do not dare to hold this ceremony on July 5 to 6 because we are afraid of the Cambodian People’s Party, but [the CPP] has never banned us.”

Yem Ponharith, CNRP lawmaker-elect, said the Sam Rainsy Party held the ceremony for years before the CNRP was founded in 2012.

“We had no intention to seek [political] gains. We only thought about the loyalty of the soldiers who were patriots and struggle to chase the yuon out of Cambodia,” he said, using a term for Vietnamese some consider derogatory.

At the event on Saturday in Phnom Penh’s Meanchey district, CNRP deputy leader Kem Sokha used the platform to announce the establishment of a “documentation centre” to investigate “crimes” perpetrated by the ruling CPP, without referencing exact incidents.

“Why do we need to create this centre? Because we know the strategy of dictators.” The centre would be based in an as yet undetermined country, he added, in order to protect the records from destruction.

“I have already contacted some Khmers and foreign friends to arrange this centre to store evidence of the crimes of the current power . . . and to make sure that your commitment has not been forgotten.

“[Your actions] have been noted; they are only waiting for [Hun Sen’s] appearance at the International Criminal Court,” he said.

Council of Ministers spokesman Phay Siphan could not be reached, and National Assembly spokesman Chheang Vun declined to comment.