News about King Bhumibol Adulyadej's health is closely monitored in Thailand, where King Bhumibol is widely revered, and the wording of palace statements on his health is intensely scrutinized. Strict laws protecting the royal family stifle any public discussion of the king's health or personal affairs including his pets.

So when the Thai palace released an unusual statement on Monday, declaring that the elderly king's health was unstable, many people in the Southeast Asian country were left alarmed, having become used to hearing most statements with a positive spin.

"The medical team are watching his symptoms and giving treatments carefully because the overall symptoms of his sickness are still not stable," the royal statement said. The comment is being widely interpreted as an admission that the monarch's life is in jeopardy.

Thailand's stock index tumbled as much as 3.6 percent on Monday and its currency, the baht, fell to more than two-month lows.

Questions about line of succession

The palace said on Saturday that the king was given haemodialysis - a way of cleansing the blood of toxins, extra salts and fluids - which made his blood pressure occasionally drop. Doctors gave him some medicine and put him on a ventilator to bring his blood pressure back to normal, the palace added.

Princess Chulabhorn, the king's youngest daughter, said in a 2011 televised statement that the king had suffered a health scare and fell unconscious after suffering from internal bleeding, likely induced by stress as a result of a flood crisis at the time.

Bhumibol is a constitutional monarch but has no formal political role. That said, he has generally been regarded as Thailand's unifying figure. However, as his health has deteriorated, his participation in public affairs has sharply declined in recent years.

Still, there are concerns that succession has been entwined with Thailand's political turmoil in the past decade, as royalists have sought to ensure that they control the process, instead of politicians who are wary of the monarchy as an institution.

jar/ksb (AP, Reuters)