The health of Thailand's king is "not stable", palace authorities said on Sunday (9 October). According to an official statement, King Bhumibol Adulyadej's blood pressure dropped as he was being prepared for haemodialysis, a procedure used to treat kidney failure.

Adulyadej, the world's longest reigning monarch, was then put on a ventilator and medication that helped return his pressure to normal levels, the statement from the palace said and added that the king had been placed under close monitor of doctors.

Last week also, the king was treated for a blood infection and a lung inflammation. Statement released from the king's palace on Saturday (1 October) had said a blood test on him revealed the infection and an X-ray found inflammation on his left lung, along with some water in his lungs.

The 88-year-old Adulyadej has been the king of Thailand for the last 70 years. He was crowned on 9 June 1946.

According to a BBC report, he is revered by Thais, for whom he has been a figure of stability through the country's decades of political upheaval.

However, due to his deteriorating health in recent years, the king has spent most of his time in hospital.

Earlier in May also, the king had received treatment for excess fluid in his spinal cord and brain. The superfluous fluid from his affected parts was drained by doctors.

The king has been treated for various health issues over the past year at Bangkok's Siriraj Hospital and was last seen in public on 11 January, when he spent several hours visiting his palace in the Thai capital.