Six suspects held in connection with the rape of a woman in India have been charged with murder after she died of injuries sustained in the attack.

The woman, who was gang-raped on a New Delhi bus on 16 December died in hospital in Singapore.

The attack has sparked protests and a national debate about violence against women.

All six suspects in the rape have been arrested and are in custody.

Elsewhere, Indian authorities have closed ten metro stations and banned access to roads in the heart of New Delhi over fears of protests in reaction to the death.

The death has brought about a security lockdown in Delhi and recognition from India's prime minister that social change is needed.

Protestors converging since the attack are demanding improved women's rights.

Candlelit vigils have been held across India following the young woman's death.

The 23-year-old medical student was severely beaten, raped and thrown out of a moving bus in New Delhi two weeks ago.

She had been flown to Singapore in a critical condition by the Indian government for specialist treatment.

The attack has sparked an intense national debate for the first time about the treatment of women and attitudes towards sex crimes.

Most rapes in India go unreported, many offenders go unpunished, and the wheels of justice turn slowly, according to social activists.

Indian Prime Minister Manmohan Singh said he was deeply saddened by the death.

He described the emotions associated with her case as "perfectly understandable reactions from a young India and an India that genuinely desires change".

Delhi's chief minister, Sheila Dikshit, said the woman's death was a "shameful moment for me not just as a chief minister but also as a citizen of this country".

The woman, who has not been identified, and a male friend were returning home from the cinema by bus on the evening of 16 December.

Six men on the bus beat them with metal rods and repeatedly raped the woman.

Both were thrown from the bus. The male friend survived the attack.

The public outcry over the attack has caught the government off-guard.

It took a week for Mr Singh to make a public statement on the attack, infuriating many protesters who saw it as a sign of a government insensitive to the plight of women.

The prime minister has struggled to channel the popular outrage in his public statements.

He also has failed to convince critics that his eight-year-old government would now take concrete steps to improve the safety of women.

Protesters, mostly young middle class students, fought pitched battles with police around the capital last weekend.

Police used batons, water cannons and teargas to quell the protests, and sealed off the main protest sites.