Authorities in northern India have arrested three men, including two police officers, suspected of gang-raping and killing two teenage sisters before hanging their bodies from a mango tree.

The deaths have sparked renewed public outrage over sexual violence in the country.

Villagers found the girls' bodies on Wednesday morning, hours after they disappeared from fields near their home in Katra village in Uttar Pradesh state, police superintendent Atul Saxena said. The girls, who were 14 and 15, had gone into the fields because there was no toilet in their home.

Hundreds of villagers spent the rest of the day in silent protest over alleged police inaction in the case. Indian TV channels showed video of the villagers sitting under the girls' bodies as they swung in the wind, preventing authorities from taking them down until the suspects were arrested.

Police arrested the three men later in the day and were searching for four more suspects.

Autopsies confirmed the girls had been gang-raped and strangled before being hanged, Saxena said.

Villagers accused the local police station chief of ignoring a complaint by the girls' father on Tuesday night that the girls were missing. The station chief has since been suspended.

The family belongs to the Dalit community, also called "untouchables" and considered the lowest rung in India's caste system.

India tightened its anti-rape laws last year, making gang-rape punishable with the death penalty. The new laws came after nationwide protests over the fatal gang-rape of a 23-year-old woman on a moving bus in New Delhi in December 2012.

Records show a rape is committed every 22 minutes in India, a country of 1.2 billion people. Activists say the figure is an underestimate because an entrenched culture of tolerance towards sexual violence means many cases go unreported. Victims' families and the police often often encouraged them to keep quiet, experts say, and those who do report cases are often subjected to ridicule or social stigma.

Last month, the head of Uttar Pradesh's governing party told an election rally that the party was opposed to the law calling for gang rapists to be executed. "Boys will be boys," Mulayam Singh Yadav said. "They make mistakes."