Police in central India say they have detained 20 men after a Swiss woman on a cycling trip was gang-raped.
Police officer D.K. Arya said Sunday that no arrests had been made so far but police were questioning the men in connection with the rape and assault on the woman and her husband in Madhya Pradesh state.
olice have registered a case of rape against seven unidentified men and were searching nearby villages.
The Swiss ambassador in India has spoken to the couple and has demanded a swift probe of the incident. The attack comes three months after the fatal gang-rape of a woman aboard a New Delhi bus outraged Indians and spurred the government to pass laws to protect women.
The attack occurred Friday night as the couple camped out in a forest in Madhya Pradesh state after bicycling from the temple town of Orchha, local police officer R.K. Gurjar said.
The men beat the couple and gang-raped the woman, he said. They also stole the couple's mobile phone, a laptop computer and 10,000 rupees (NZ$200).
The woman, 39, was treated at a hospital in the nearby city of Gwalior, Gurjar said.
A photo showed the woman walking while being escorted by police to the hospital. Her face was concealed with a hood, a common practice in India, where law does not allow rape victims to be identified publicly to protect them from the stigma attached to rape in the conservative country.
Police detained 13 men and questioned them, Gurjar said. Six of the men were released after questioning. No other details were immediately available.
Indian television stations showed scores of police searching the forest where the attack occurred.
Swiss Foreign Ministry spokesman Tilman Renz described the case as "deeply disturbing" and said Swiss diplomats were assisting the couple.
The diplomats called on Indian authorities "to do everything to quickly find the perpetrators so that they can be held accountable," Renz said in a statement.
Last month, the Swiss government issued a travel notice for India that included a warning about "increasing numbers of rapes and other sexual offenses" in the South Asian nation.
India has seen outrage and widespread protests against attacks on women since December's fatal gang-rape of a young woman on a moving bus in New Delhi, the capital. The crime horrified Indians and set off nationwide protests about India's treatment of women and spurred the government to hurry through a new package of laws to protect them.
One of six suspects in the December attack was found dead in a New Delhi jail this past week. Authorities said he hanged himself, but his family and lawyer insisted foul play was involved. A magistrate is investigating. Four other men and a juvenile remain on trial for the attack.