LUCKNOW, India (AFP) - Indian police on Thursday arrested six men accused of gang-raping and murdering two teenage sisters whose bodies were found hanging from a tree outside their village, prompting protests.

The sisters aged 15 and 17 were from the Dalit community, the lowest rung in the Hindu caste system, who suffer disproportionately high levels of sexual violence in a country with high rates of crime against women.

Local police chief Sanjiv Suman said the men had on Wednesday lured the girls to a field where they sexually assaulted them and then "killed them by strangling them with their scarves".

Scores of locals including the family of the teenagers held street protests near their village in the northern state of Uttar Pradesh, demanding swift punishment for the accused.

One of the main suspects, who was a neighbour of the girls, was arrested following a firefight with police when he was shot in the leg. The accused belonged to both the Hindu and Muslim communities.

An autopsy report confirmed sexual assault and asphyxiation as the cause of death, Suman said.

Nearly 32,000 cases of rape were reported in India in 2021, according to government figures, but many more are thought to go unreported.

Last year, the Uttar Pradesh authorities' swift cremation before an autopsy of a Dalit rape victim murdered by an upper-caste Hindu man triggered widespread outrage.

The latest incident is reminiscent of the rape and murder of two cousins aged 14 and 15 from the Dalit community in 2014 in the same state, which prompted an uproar.

The girls were found hanging from a mango tree and police initially accused local upper-caste men of sexually assaulting and killing them but the police investigation was bungled and no one has been convicted.