"Our medical team's investigations upon her arrival at the hospital yesterday showed that in addition to her prior cardiac arrest, she also had infection of her lungs and abdomen, as well as significant brain injury," said Dr Kelvin Loh, Chief Executive Officer, Mount Elizabeth Hospital.
In a statement, Dr Loh said, "The patient is currently struggling against the odds, and fighting for her life."
Briefing reporters here on girl's condition, Loh said, "As at 28 December, 11am (8:30 IST) the patient continues to remain in an extremely critical condition."
The girl, who was gang-raped and brutally assaulted in a moving bus on December 16, was brought here in an air ambulance yesterday and admitted to the Intensive Care Unit.
She had undergone three surgeries at the Safdarjung Hospital in Delhi, where she remained on ventilator support during most part of the treatment. Doctors removed major part of her intestines which had become gangrenous.
"A multi-disciplinary team of specialists has been working tirelessly to treat her since her arrival, and is doing everything possible to stabilise her condition over the next few days," Dr Loh said.
"The High Commission of India has been fully supportive in helping the hospital and her family, and ensuring that the best care is made available," he added.
The security was tightened at the hospital, favoured by well-heeled patients, with each visitor screened before being allowed into the ICU.
In Delhi, Congress chief Sonia Gandhi stressed that no time should be lost in bringing the perpetrators of such barbarous act to justice.
Prime Minister Manmohan Singh assured that those found guilty of lapses in the aftermath of the incident will not be spared.
"We are committed to bringing the guilty to justice as soon as possible," Singh said, adding that best possible medical care was being provided to the victim.
The victim's father, who flew in with her, said he was reassured that the best is being done for his daughter.
The girl's family members do not speak English and rely on interpreters to communicate with hospital staff, the Strait Times newspaper reported.
The High Commission of India has assigned a liaison officer with the family.