A 35-year-old Nigerian woman, who has been staying in India on a tourist visa, was gang-raped in a moving car in the early hours of Friday.
The unlucky woman was said to have been kidnapped outside a popular shopping mall in Saket, an area in New Delhi, capital of the country, before being bundled into a car.
The woman was finally rescued after a passerby spotted her on the side of the road in Mayur Vihar, around 20 kilometres (12 miles) away in east Delhi.
The victim told the police that she was driven around the city when the assault was ongoing and was pushed out of the vehicle after the ugly experience.
“We have received a complaint from the woman and investigations are ongoing,” Delhi police spokesman Rajan Bhagat told AFP.
“We have filed a case under relevant sections.”
Bhagat said the four men arrested were Indians, and the car allegedly used had been impounded.
Local media, quoting police sources, said the victim was in an inebriated condition at the time of her rescue and had suffered minor injuries but was released from hospital by Friday afternoon.
Nigerian embassy officials in New Delhi are yet to react to the issue.
There have been series of sex attacks in the Asian country.
Two years ago, a medical student died after being gang-raped on a moving bus, prompting mass protests and triggering a series of policing and legal reforms.
Last year, a driver for US-based online taxi service Uber allegedly sexually assaulted a woman passenger in New Delhi while driving her home from a dinner.
Police figures released earlier this year said 2,069 rape cases were registered in New Delhi during 2014, a 31 percent jump compared to the previous year.