A Facebook user photographed in military fatigues with an army ID has posted a video to social media threatening to arrest and shoot a pro-opposition migrant worker in South Korea for challenging Prime Minister Hun Sen to a duel.

A Defence Ministry official could not immediately confirm whether Facebook user Kang Buntou was indeed a soldier yesterday, but the Korea-based activist, Sot Silat, said his mother had recently been “threatened” by men identifying themselves as government officials.

Buntou – listed as working for an organisation called Youth Network for Humanity – posted the video on Facebook in response to social media posts from Silat criticising Hun Sen’s recent threat to attack former opposition leader Sam Rainsy with a BM-21 rocket battery.

“Today I go to South Korea to arrest and bring him back for punishment, and I might shoot him if he dares to challenge me,” Buntou says in the video, which has since been deleted. The video was accompanied by photos of Buntou standing outside Phnom Penh International Airport with what appeared to be a handgun tucked into his pants.

Defence Ministry spokesman Chhum Socheat said he would look into whether Buntou was in the military, but said even if he were, his statements were strictly personal.

Speaking from Korea yesterday, Silat said other officials had visited his mother and uncle to get him to apologise for attacking the premier, adding that he was only joking about the duel because he was “fed up with Hun Sen activities that mistreat people”. His mother, Sok Bean, said she was visited by officials who would only say that they were from a “ministry that sent her son abroad”, and that her son needed to stop his critical social media posts.

Additional reporting by Ananth Baliga