The condition of the 23-year-old victim of a gruesome gang-rape in Delhi, admitted in a super-speciality hospital here yesterday, has taken a "turn for the worse" tonight with signs of severe organ failure.

"As of 9 pm (6:30 PM IST), the patient's condition has taken a turn for the worse. Her vital signs are deteriorating with signs of severe organ failure," Dr Kelvin Loh, Chief Executive Officer, Mount Elizabeth Hospital said in a statement.

"This is despite doctors fighting for her life including putting her on maximum artificial ventilation support, optimal antibiotic doses as well as stimulants which maximise her body's capability to fight infections," the CEO said.

"Her family members have been informed that her condition has deteriorated and they are currently by her side to encourage and comfort her," he added.

The statement said the hospital's medical team continues to "provide all possible treatment and care", to the victim, who was air-dashed from the Safdarjung Hospital in Delhi for specialised treatment.

He said the the High Commission of India is with her and her family at this critical time.

Earlier in the day, the security was tightened at the hospital, favoured by well-heeled patients, with each visitor screened before being allowed into the ICU.

The victim's father, who flew in with her, said he was reassured that the best is being done for his daughter.

The girl was shifted to the hospital here following what the Indian government said a "purely a medical decision" taken by doctors.

Earlier in the day, the hospital said that she has significant brain injury, infection in lungs and abdomen and is struggling against all odds, the hospital had said.

"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, 11 am (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 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.

Meanwhile, Indian High Commissioner to Singapore Dr T C A Raghavan said the girl is getting the best medical attention and multi-discipline surgeons are attending to her.

"We are hoping for the best," Raghavan told PTI.

"Her family is aware that she is getting the best medical treatment at the hospital. The family is attending to her and we are trying to keep them near her," he said.

The High Commissioner stressed the importance of respecting the privacy requested by the family.