Police in India's financial capital, Mumbai (Bombay), are investigating the alleged assault of two young women early on New Year's day.
Nearly 70 men were reportedly involved in the incident near a top hotel in the city's Juhu area, which was captured on camera by two newspaper photographers.
The men are seen surrounding the women after they left the hotel.
Police have yet to make any arrests in the case. The incident has fuelled fears about women's safety in the city.
The Hindustan Times newspaper, whose staff photographed the incident, reported that the two women left the five-star hotel with two men after attending New Year celebrations.
The women were teased and harassed by a crowd of men outside, the paper said.
One of the women had her clothes torn in the incident which went on for about 20 minutes, it added.
The crowd dispersed only after the photographers called two policemen who were on duty in the area.
"I got to know about the incident this [Wednesday] morning and since there was no formal complaint in this matter, the police will lodge one," Mumbai police commissioner, DN Jadhav, said.
He said investigations were continuing.
Senior police officer Archana Tyagi told a television channel that the police had deployed 100% of its force in Mumbai on the New Year's eve.
Last New Year's eve, a woman was the subject of an alleged assault at the Gateway of India in Mumbai, one of the country's most famous landmarks.
Again, the incident was caught on camera by a photographer for a local paper.
Police said they could only take action against the woman's alleged attackers if she pressed charges.
The incidents have damaged the image of Mumbai which is generally believed to be safe for women.
"Mumbai is a safe city but what happened is very unfortunate. Outsiders like tourists will think that this place has become unsafe. Government should take strict action against the offenders," said Mumbai resident Sameer.
Shyamli, a business executive, said: "What has happened is wrong. I am shocked. I was at Juhu at 4am that night and saw many policemen there. But now I feel Mumbai is a little unsafe for girls."