Former Indonesian president Suharto, who was rushed to hospital in critical condition last week, deteriorated on Tuesday as doctors tried to avert multiple organ failure.
The medical team said there was little room for optimism.
Suharto, 86, is admitted to Pertamina Hospital, one of Jakarta's top medical centres since Friday, where a team of 40 doctors is treating him for heart, lung and kidney problems.
"Suharto is in a highly unstable condition and requires intensive monitoring," Mardjo Soebiandono, the head of the medical team treating the former five-star general, told reporters.
"More fluid infiltrated his lungs and some blood was seen in his faeces and urine that prompted his haemoglobin to drop," he said, adding that Suharto had been given a blood transfusion.
Reporters at the hospital saw Suharto being wheeled out of the radiology unit, accompanied by his three daughters, who were crying.
Juniarti Hatta, a cardiovascular expert and a member of the medical team, later told reporters the former president's left heart chamber had swollen to a point that could lead to heart failure.
Suharto ruled Indonesia for over three decades until he was ousted in 1998.
The former strongman has been living in a family compound in the heart of Jakarta since then.
Critics say he and his family amassed billions during his rule, but the former president and members of his family have denied any wrongdoing.
Despite Suharto's humiliating ouster in 1998 and the subsequent attempts to prosecute him for corruption, members of Indonesia's political and business elite have been flocking to his bedside to pay their respects, a mark of his lingering influence.
President Susilo Bambang Yudhoyono and Vice President Jusuf Kalla visited at the weekend, while Central Bank Senior Deputy Governor Miranda Goeltom, Communication and Information Minister Muhammad Nuh, and Social Welfare Minister Aburizal Bakrie dropped by on Monday.
Huge flower arrangements from wellwishers almost blocked the corridor leading to the hospital lobby.