The 9th statement released Thursday by the hospital said the overall condition of His Holiness had worsened and he died at 7.30pm.
He died of sepsis (a blood infection), according to the statement.
His Majesty the King has acknowledged the death of His Holiness with deep sorrow, the Royal Household Bureau said in a statement issued last night. His Majesty instructed that the Supreme Patriarch's body should lie in state at Phra Tamnak Petch at Wat Bowon Niwet in Bangkok and that palace officials must wear black for 15 days, starting Friday.
The public can pay their respects to the body of His Holiness at Chulalongkorn Hospital's Wachirayannawong Building from 9am until noon Friday before his body is moved from the hospital to the Manusayanak Witthayatharn Building at Wat Bowon Niwet.
The public can attend the bathing rite before a picture of the Supreme Patriarch at the Manusayanak Witthayatharn Building in the compound of Wat Bowon Niwet from 1pm daily.
Prime Minister's Office permanent secretary Tongthong Chandransu Thursday said the government has declared a 15-day mourning period for His Holiness with flags to be lowered to half-mast for three days. Government officials nationwide have also been told to wear black for 15 days, Mr Tongthong said.
In the eighth hospital statement released earlier Thursday, the general condition of the Supreme Patriarch had deteriorated with a drop in his blood pressure. A team of physicians had been monitoring his condition closely.
The Supreme Patriarch received surgery to treat an intestinal infection on Oct 14.
A group of monks and Buddhists who were following the Supreme Patriarch's condition at Chulalongkorn Hospital joined in prayers for his health to improve.
The Supreme Patriarch had been ill since Feb 20, 2002 when he was admitted to Chulalongkorn Hospital.
He turned 100 on Oct 3, when Buddhists nationwide held religious ceremonies to wish him good health.
More than 3,000 people came to the hospital that day to sign the well-wishers' book.
Somdet Phra Nyanasamvara was appointed by His Majesty the King as the head of the Buddhist clergy in 1989, the 19th Supreme Patriarch since the beginning of the Chakri Dynasty. At 24 years in the role, His Holiness was the longest-reigning Supreme Patriarch.
His Holiness was born on Oct 3, 1913 in Kanchanaburi province. He was formerly known as Charoen Gajavatra.
When he completed Prathom 5 at the age of 14, he was ordained as a novice at Wat Devasangaram (Wat Nua), Kanchanaburi.
A year later, Novice Charoen was accepted by Somdet Phra Vajirananavong, the abbot of Wat Bowon Niwet to undertake Buddhist studies, completing the basic curriculum as well as learning the Pali language.
His Majesty the King bestowed the title of Somdet Phra Nyanasamvara _ a special honour in the Thai monastic hierarchy reserved for monks who excelled in Vipassana meditation that had not been granted in over 150 years _ to Phra Sasanasobhon in 1972.
The World Buddhist Supreme Conference last year bestowed the title of the Supreme Holiness of World Buddhism on the Supreme Patriarch during a Buddhist summit in Japan, attended by Sangha leaders from 32 nations worldwide.