Indian authorities added murder charges Saturday for suspects in the brutal gang rape that led to the death of a 23-year-old woman and sent outraged protesters to the streets.
The suspects already faced rape charges.
Six people, including a minor and a bus driver, have been arrested in connection with the rape that occurred in New Delhi this month.
Throngs of people have protested for days, demanding more protection for women and punishment for those behind the assault.
The woman was airlifted to Singapore earlier this week after she was treated for injuries in a New Delhi hospital.
Singapore doctors said she died "peacefully" early Saturday, surrounded by her family and Indian embassy officials.
The woman had been in "extremely critical condition" since her arrival Thursday and took a turn for the worse, said Dr. Kelvin Loh, chief executive officer at Mount Elizabeth Hospital.
"She had suffered from severe organ failure following serious injuries to her body and brain," Loh said. "She was courageous in fighting for her life for so long against the odds, but the trauma to her body was too severe for her to overcome."
The victim's body was returned to India, where it was cremated Sunday in a private funeral, Home Ministry spokesman K.S. Dhatwalia said.
The U.S. Embassy in New Delhi expressed its condolences Saturday.
"As we honor the memory of this brave young woman, we also recommit ourselves to changing attitudes and ending all forms of gender-based violence, which plagues every country in the world."
Authorities have not released the name of the woman, but Indian protesters are calling her Damini, which means "lightning" in Hindi.
"Damini" is also a 1993 Bollywood film whose lead female character fights for a housemaid, a victim of sexual assault.
The Times of India calls her Nirbhaya, which means "fearless."
Susan Rice, U.S. ambassador to the United Nations, wrote on Twitter, "To our friends in India: we share your outrage over an act of unimaginable cruelty against one of our sisters. RIP Nirbhaya."
India's ambassador to Singapore said the victim's relatives, who are Hindus and live in New Delhi, have asked for privacy.
Attackers assaulted the woman and her male companion on a bus December 16, robbing them of their belongings before dumping them at the side of a road, police said.
The male companion was eventually discharged from a hospital.
Last week, police said the woman recovered enough to give a statement to a magistrate from her hospital bed. But she had more surgery to wash out infection in her abdomen, her doctors said.
The death spurred an outpouring of sadness and calls for action to ensure change and punishment of her rapists.
Fearing massive protests following the death, police tightened security in the capital and barricaded some sites of previous rallies.
Authorities said demonstrations are only allowed at Jantar Mantar observatory and the Ram Lila grounds.
Police banned protests in Raisina Hills and closed roads leading to the area, fearing a possible repeat of the furious, large-scale demonstrations that occurred last weekend. Ten metro stations also were ordered closed, authorities said.
Additional protests were planned Sunday in several cities, activists told CNN affiliate IBN.
Prime Minister Manmohan Singh offered his "deepest condolences."
