The health of Thailand's King Bhumibol Adulyadej, the world's longest reigning monarch, who has been reigning for 70 years, has "overall not yet stabilised".
On Sunday the palace announced that the king was in an unstable condition after receiving hemodialysis treatment.
King Bhumibol, 88, is widely revered, and a crowd of well-wishers have gathered outside Siriraj hospital.
Prime Minister Prayuth Chan-ocha cancelled an official engagement to meet the Crown Prince.
Reports state, the king's blood pressure has lowered and breath has quickened, his liver and kidneys are not working properly and he remains on a ventilator.