India rape protest
Students protest in New Delhi against a series of rape and sex attacks that have left women dead, causing outrage across the countrySAJJAD HUSSAIN/AFP/Getty Images

Indian police have detained 15 men over a three-hour gang rape at gunpoint of a mother and her 14-year-old daughter while male relatives were tied up nearby. The attack occurred off a major highway after the attackers hurled an iron bar at the car that the 35-year-old woman, her daughter and four male relatives were traveling in.

When the driver pulled over and got out to see the damage near Bulandshahr, in the northern state of Uttar Pradesh, the men moved in brandishing guns, police told the Times of India.

They separated the mother and daughter from the men, forced the driver to steer the car into a swampy field and tied up all the men. They included the woman's husband, who is the father of the teenager. They were robbed of money, jewellery and mobile phones.

Police said that they were still searching for the ringleader. "The main suspect has been identified. We are trying to arrest him as soon as possible and send him to jail under stringent sections of the law," police spokesman Daljeet Chaudhary told Agence France Presse. Three to five men have been charged over the attack.

Five local police officers were suspended for dereliction of duty, and two police stations suspended for negligence, according to India Today, which provided no other details.

The victim's husband has vowed to commit suicide if the attackers are not punished within three months, said the newspaper.

India has been stepping up a crackdown on violence against women after a medical student was gang-raped and killed on a bus in Delhi in 2015. But the incredibly brutal attacks appear to be continuing unabated.

Earlier this year, a 15-year old girl was raped, murdered and hanged from a tree to make it appear that her death was a suicide. A university student was recently gang-raped by the same men who had attacked her before.