BANGKOK - Hundreds of teary Thai citizens gathered at Bangkok's Siriraj Hospital on Thursday (Oct 13) afternoon in anticipation of an imminent announcement on the condition of ailing King Bhumibol Adulyadej.

Prime Minister Prayut Chan-o-cha has reportedly cancelled a scheduled trip to India. Meanwhile, Bangkok Post has reported that all National Legislative Assembly members have been told to prepare for a special meeting at 9pm Bangkok time (10pm Singapore time).

A hall in Bangkok's Grand Palace, which has been receiving people sending their well-wishes to the 88-year-old monarch, was closed on Thursday, according to local daily Khaosod.

King Bhumibol, the longest reigning monarch in the world, has been battling a range of ailments over the past few months, including lung infection, renal failure, as well as hydrocephalus, a condition commonly referred to as "water on the brain".

A statement issued by the Royal Household Bureau on Sunday evening said, for the first time, that his condition was "unstable".

This was followed by another statement on Wednesday evening that said that his overall condition remained unstable.

"The result of the blood test showed that there was an infection, and his liver was not in a regular condition," it said. Doctors gave him antibiotics, put him on a ventilator, and also on continuous renal replacement therapy (CRRT).

CRRT is usually given to critically ill patients.

The King is revered and often referred to as the father of the nation.

Retiree Chumjit Keuwsinvan, 80, who was among those praying fervently at Siriraj Hospital, told The Straits Times: "If I can trade places with him, I will, right away, right now. I love him more than life."