A man walks past a graffiti depicting a message in protest against rape in India. File picture: REUTERS/Mukesh Gupta

New Delhi - Two teenagers have been gang raped in separate incidents in India in the past four days, highlighting a rape epidemic that shows no sign of abating despite tougher penalties introduced last month.

Police said they had not made any arrests in either case.

One victim was a 16-year-old girl who committed suicide after being raped by eight men on Sunday in the Nuh district of the northern state of Haryana, senior police official Nazneen Bhasin told Reuters.

On Tuesday, a 19-year-old woman was raped by five men, including the driver of an autorickshaw she hailed in another district of the same state.

The driver duped the woman into believing that she had missed her bus and offered to drop her off at another bus depot, said a police spokesman, Ravindra Kumar, citing the victim's complaint.

She was then taken to a deserted area near Gurugram town and raped by the driver and four accomplices who were waiting there, Kumar said.

"A case of gang rape has been registered after the medical examination of the victim confirmed the same. The matter is under investigation," Kumar said.

Gurugram, on the southwest outskirts of New Delhi, is a rapidly expanding satellite town, where scores of international companies have set up offices due to its role as an industrial, financial and technology hub.

Media reports said the 16-year-old girl was abducted from her home when she was alone and raped by men from her village. The victim hung herself on Monday and the police has registered a case of rape, kidnapping and abetment of suicide though the perpetrators had not been caught.

The incidents come less than a month after India approved the death penalty for the rape of girls younger than 12, and increased the prison term for the rape of older girls and women following nationwide disgust over a particularly gruesome rape and murder of a Muslim girl in Jammu & Kashmir state.

Registered cases of sexual violence have been steadily rising despite the national outrage that followed the fatal gang rape of a student on a bus in New Delhi in 2012.

Amid the wave of anger at that time, the government promised to speed up rape trials, introduce harsher penalties, including the death sentence in extreme cases, and introduced a law against stalking.

But statistics show that since 2012, reported rape cases climbed 60 percent to about 40,000 in 2016, with child rape accounting for about 40 percent of them.