File photo taken on Dec. 5, 2013, released by Thailand's Royal Household Bureau, shows Thai King Bhumibol Adulyadej attending a ceremony to mark his 86th birthday at Klai Kangwon Palace in Prachuap Khiri Khan Province, Thailand. According to Thailand's Palace Statement, Thai King Bhumibol Adulyadej passes away on Oct. 13, 2016. (Xinhua/Thailand's Royal Household Bureau)
Thai King Bhumibol Adulyadej was pronounced dead on Thursday after years of grave illnesses, leaving the throne to Crown Prince Maha Vajiralongkorn.
The Bureau of the Royal Household announced that the 88-year-old monarch died in quiet manner at 3:52 p.m. (0852 GMT) at Siriraj hospital where he had been diagnosed with critical ailments since the last several years.
King Bhumibol, or King Rama IX of the Chakri dynasty, who had been the world's longest-reigning monarch for the last 70 years, is survived by 63-year-old Crown Prince Maha Vajiralongkorn, who is to be officially proclaimed King Rama X.
Prince Vajiralongkorn, King Bhumibol's only son, was named Crown Prince, the heir apparent to the throne in 1972 in accordance with the Palace Law.
Prime Minister Prayut Chan-o-cha called on the Thai people to mourn the king's death for one full year and Thai flags will fly at half-mast for one month beginning on Friday.
"Today is one of the Thai people's greatest losses since the day King Rama VIII passed away," the premier said in a nationwide broadcast statement, referring to King Ananda Mahidol, King Bhumibol's elder brother, who died at the age of 21.
King Bhumibol, who rose to the throne in 1946, was son of Prince Mahidol Adulyadej and Princess Srinagarindra. He was born in Cambridge, Massachusetts, the United States in 1927.
The then-Prince Bhumibol grew up in Lausanne, Switzerland before he accompanied his elder brother, King Ananda Mahidol or King Rama VIII, to Thailand in 1928.
The then-Prince Bhumibol was pronounced monarch to succeed his brother on June 9, 1946
In 1950, King Bhumibol was married to Queen Sirikit Kitiyakara.
King Bhumibol is survived by his four children, namely Crown Prince Maha Vajiralongkorn, former princess Ubolratana Rajakanya, Princess Maha Chakri Sirindhorn and Princess Chulabhorn Walailak.
The late monarch was dubbed King of Agriculture as he was widely known for his initiatives on the agricultural and irrigational sector, which were formulated into some 4,000 development projects throughout the country during the last several decades.
He was as well noted for initiating the so-called sufficiency economy, which was not only promoted in Thailand but also in other developing countries.
The late king's pictures and drawings were seen along the roads, in the government premises and the houses of many villagers throughout the country.
Many projects implemented by successive Thai governments, as well as by the private sector, had been implemented under guidelines and initiatives of the late king, particularly those involving agricultural and irrigational measures and rainmaking technology for drought-affected areas in the country.