Image caption The victim is being treated at a specialised facility in Singapore 
 
 A female student who was gang-raped on a bus in India's capital Delhi has arrived in Singapore for further treatment, officials say. 
 
 The 23-year-old victim - who remains on life support - is being treated at a specialised facility and may require an organ transplant. 
 
 The attack earlier this month triggered violent public protests, which left one police officer dead. 
 
 An inquiry into possible lapses by the authorities is now under way. 
 
 The investigation is being led by retired judge Usha Mehra. 
 
 Six men have been arrested and two police officers have been suspended following the 16 December attack. 
 
 An air ambulance carrying the woman landed at Singapore Changi International Airport early on Thursday, the Indian High Commission in Singapore told news agencies. 
 
 The victim - who has already had three operations in Delhi - was then taken to the city's Mount Elizabeth hospital. 
 
 The hospital said in a statement quoted by the Associated Press that she was admitted to the intensive care unit "in an extremely critical condition". 
 
 "She is being examined and the hospital is working with the Indian High Commission," the statement said. 
 
 'Prolonged treatment' 
 
 Senior Delhi doctor BD Athani told the Press Trust of India that the hospital had "a state-of-art multi-organ transplant facility" to treat the victim's severe intestinal injuries. 
 
 The woman's family have accompanied her to Singapore because the treatment might take a long time, Dr Athani added. 
 
 Police in Delhi have opened roads and metro stations shut since Monday as protests against the incident eased. 
 
 The government has tried to halt the rising anger by announcing a series of measures intended to make Delhi safer for women. 
 
 These include more police night patrols, checks on bus drivers and their assistants, and the banning of buses with tinted windows or curtains. 
 
 The government has also said that it will post the photos, names and addresses of convicted rapists on official websites to shame them. 
 
 But the protesters say the government's pledge to seek life sentences for the attackers is not enough - many are calling for the death penalty. 
 
 The victim and her friend had been to see a film when they boarded the bus in the Munirka area, intending to travel to Dwarka in south-west Delhi. 
 
 Police said she was raped for nearly an hour, and both she and her companion were beaten with iron bars and thrown out of the moving bus into a Delhi street. ||||| Image caption There have been nationwide protests against the incident 
 
 Police in the Indian capital say they have arrested a fifth person in connection with the gang rape on a bus of a young woman on Sunday. 
 
 Four people, including the bus driver, have already been arrested. 
 
 The 23-year-old woman remains in a critical condition in a Delhi hospital. 
 
 There has been outrage in India in the wake of the attack on the woman and her male friend. The government has since announced a series of measures intended to make Delhi safer for women. 
 
 They include more police night patrols, checks on bus drivers and their assistants and the banning of buses with tinted windows or curtains. 
 
 "The fifth accused has been arrested in the rape case. His age is being verified before giving details. If [he is a] minor, we have to hold back his particulars as per law," Delhi police chief Neeraj Kumar was quoted as saying by the Press Trust of India. 
 
 The men arrested in connection with the incident earlier also include a gym instructor and a fruit seller. 
 
 Fresh protests demanding stringent punishment for the rapists were held outside Delhi's presidential palace, or Rashtrapati Bhavan, on Friday. 
 
 The woman has undergone two rounds of surgery since Sunday and remains on life support, doctors at Delhi's Safdarjung Hospital said. 
 
 Angry MPs have demanded the death penalty for the rapists, and protests and candle-lit vigils have been held in the capital and elsewhere in India. 
 
 The woman and her friend boarded the bus in Munirka area and were on their way to Dwarka in south-west Delhi. 
 
 They were returning after watching a film in a shopping centre in south Delhi, police said.
– The woman who was gang-raped on a New Delhi bus has been flown to Singapore for treatment. The 23-year-old remains in 'extremely critical condition,' says a hospital rep, and she may need an organ transplant. India's government fears that continuing protests—which have already seen the death of a police officer, the BBC notes—could grow depending on the woman's fate, the Times of India reports. And it adds that her health has only worsened: She suffered a cardiac arrest on Wednesday, and is fighting sepsis, which must be dealt with before an intestine transplant can be considered. Authorities, led by a retired judge, are conducting an inquiry into the official response to the assault. Two police officers have been suspended amid concerns that authorities have looked the other way while women are attacked. The protests earlier prompted a citywide lockdown, but roads and subway stations are beginning to reopen, the BBC adds.