Prime Minister Hun Sen’s second-eldest son, Hun Manith, has thrown cold water over the opposition’s attempts to distance itself from pending anti-government protests in the US next week when the prime minister attends a US-ASEAN summit in California.

The US-based Cambodia-America Alliance said last month that they expected up to 1,000 members to attend anti-Hun Sen demonstrations in California on February 15 – an event that marks the first time the prime minister has been invited by a US president to visit the country.

Hun Sen has warned, however, that US protests would spark ruling-party demonstrations against opposition leaders in Cambodia. The premier made similar threats when he was greeted by anti-ruling party protesters on a trip to Paris in October. The pro-government protests that followed ended with two opposition lawmakers savagely beaten outside the National Assembly.

On Saturday, a video began circulating in local media showing Cambodia National Rescue Party president Sam Rainsy addressing supporters in Washington. The opposition leader appeals to the CNRP’s US base to refrain from political protests in California.

“This demonstration now is not good; it will damage the CNRP’s work,” Rainsy says in the video.

He goes onto say that the CNRP does not endorse or recognise any protesters attending the rally, calling for “calm” and “patience” as the party seeks to realise its political aspirations.

“Many views supporting the CNRP understand the situation; what we should do and what we should not do in order to achieve our goal, to rescue our nation in a peaceful way,” he said.

But the prime minister’s son, Manith, who was also promoted to the head of the army’s intelligence unit in 2015, told local media last week he had infiltrated online “group communications” and had evidence that the CNRP was behind the planned anti-Hun Sen protests.

“Although Mr Sam Rainsy and the CNRP leaders recently made an announcement denying it, the preparations continue,” he said. “[Rainsy] is trying to create an image that they are not related [to the protest], but planning is under way.”

Contacted yesterday, Manith declined to comment further, but stood by his comments in local media.

Political analyst and founder of the Future Forum think tank, Ou Virak, described both parties’ responses as “puzzling”, as such events are common in democratic political debate.

The ruling party, he said, have become “obsessed” with trying to protect the opportunity for legitimacy that a handshake with US President Barack Obama presents for Hun Sen.

“They don’t want to ruin the mini-victory lap,” Virak said.

Meanwhile, the opposition, which has long-encouraged political demonstrations in Cambodia, appeared “scared”, Virak added, seeking short-term political gains rather than sticking to their principles.

Additional reporting by Daniel de Carteret