An Indian court has sentenced to death the four men convicted in the December gang rape and murder of a young New Delhi woman.

They are to be hanged for the brutal attack on a moving bus that left the young woman with such severe internal injuries that she died two weeks later.

The death sentence, handed down today, must be confirmed by India's High Court. The men can appeal to the Supreme Court, and ask the president for clemency.

The 23-year-old victim's family, with numerous politicians and government officials, had long called for the men to be executed. The case has been closely followed across India, seen as a reflection on rampant mistreatment of women and the government's inability to deal with crime.

In calling for the four to be hanged, prosecutor Dayan Krishnan said the attack shocked India's "collective conscience", noting that the police report showed the men pulled out some of the victim's body parts after savagely violating her with an iron rod.

"There can be nothing more diabolic than a helpless girl put through torture," Mr Krishnan said.

India's Supreme Court has ruled that the death penalty should be used only in "the rarest of rare cases", though what defines those cases remains highly debated.

By most estimates, more than 100 people are sentenced to death in India in most years, but the vast majority of those cases are eventually commuted to life in prison.