Prime Minister Hun Sen announced on Facebook yesterday that he had fallen ill with exhaustion and was currently seeking medical treatment in Singapore.

The urgent trip saw Hun Sen postpone engagements in Kampong Speu with civil servants and armed forces, and cancel scheduled meetings with representatives from Japan, India and France.

“Because I am very tired I have become so ill that I needed to go to hospital urgently for a medical check-up and treatment,” he wrote in a Facebook post.

The premier posted a series of photos of himself in a hospital bed with his eldest son, Hun Manet, and his grandson alongside him, saying he arrived at the Singapore hospital at 2pm on May 3 and would return to Cambodia on May 7 to “continue my work as usual”.

Hun Manith, the prime minister’s second son, yesterday thanked journalists for their concern but declined to comment further on his father’s condition.

Hun Sen, often labelled a “strongman” of Southeast Asia, is rarely pictured in a state of vulnerability, but political analyst Ou Virak said with yesterday’s post, the premier had managed to take control of the political message.

“It’s definitely showing his vulnerability, but I don’t see many other options,” he said. “I think it’s actually smart because the post is showing him in a stable condition ... Either you have that or you have rumours, and the Cambodian rumour mill is pretty famous for producing juicy conspiracy theories.”

“The message in the Facebook post is that he is working really hard for the country and he pays the price with his health, but they have got to have a healthy person to lead their country.”

But, he added, the post also inadvertently highlighted Hun Sen’s mortality and, by extension, the need to formulate a plan for a smooth transfer of power. Hun Sen has maintained a firm grip on power in Cambodia for more than 30 years.

“The problem of Cambodia is I think we need him; it’s basically his creation, he created a system where he is needed. That’s the risk that needs to be addressed,” Virak said.

Social researcher Meas Ny said Hun Sen appeared to have taken a weakness and turned it into a kind of strength – or at least a humanising force – adding that the “Facebook premier” often posted about his health check-ups on social media.

“Many thousands of supporters are sending well wishes; nobody dares to say anything negative,” Ny said. So far, more than 11,000 people have commented on and shared the premier’s post.

“It’s also a test ... It gauges support for the [Cambodian People’s Party], it’s a tool to assess how much people love him.”

Ny, who clarified he did not know the extent of the premier’s condition, said stress from the past year of all-out politicking could have had an impact on Hun Sen’s health.

“I think it’s probably part of the stress. Over the last year, the CPP has shown more power and more muscle, and that might contribute to a lot of stress,” Ny said, noting that the apparent shows of force appeared not to have had the intended effect.

“His political manipulation sometimes works, and sometimes it elicits a strong reaction from the people and from his own party as well, but ultimately CPP did not get any benefit at all . . . it was less effective.”

In the past, however, Hun Sen has taken his medical ailments in stride. At the height of election season in 1998, a pajama-clad Hun Sen emerged from hospital, shortly after emergency surgery to remove his appendix, to playfully spar with international media.

Lighting a 555 cigarette, he announced “smoking means I am healthy”, before going on to promise that elections would be free and fair and that he had no means to influence the ballot box.

“I can’t even tell my daughter how to vote. I think she will vote for me, but I’m not sure,” he said.

Additional reporting by Khouth Sophak Chakrya