Zeev Rotstein, of Tel Hashomer hospital, said that the functioning of “several essential organs” has declined but would not elaborate.
Mr Rotstein said Mr Sharon’s condition is “critical” and his “life is in danger”. He said Mr Sharon’s family was at his bedside.
The 85-year-old has been in a coma since 2006 when a devastating stroke incapacitated him at the height of his political power. He was one of Israel’s most iconic and controversial figures. A prominent hard-line voice over the decades, he was elected prime minister in 2001.