Five men have confessed to gang-raping a Swiss woman as she camped with her husband in India, police said Sunday.

The couple were camping at a village in Datia district of Madhya Pradesh state on Friday during a cycling trip when they were attacked by a group of men.

Police detained at least 20 people after the attack.

"We have detained five men and they have confessed to gang-raping the woman and attacking her husband," police official M.S. Dhodee told Agence France-Presse.

He added that police were searching for a sixth perpetrator.

The men arrested are all reportedly members of the Kanjar tribe, a historically nomadic ethnic group who, traditionally, sold rope and other crafts to villagers, but who also have a reputation for violence, kidnapping, and "dacoity", or banditry, the Sydney Morning Herald reported.

Dhodee said the attack was a spur-of-the-moment crime of opportunity.

"They were passing by, noticed the couple putting up their tent and saw an opportunity to attack and rape the woman."

The victim, who is reported to be 39 years old, and her husband had been cycling from Orchha to Agra, to see the Taj Mahal, a distance of about 250km (155 miles), when they decided to camp for the night in a forested area.

One report cited the victim's husband as saying the group of men approached them, beat him with wooden sticks before tying him up and sexually assaulting his wife in front of him.

The assailants stole the couple's valuables, including 10,000 rupees ($185) and a laptop computer, before fleeing into the woods.

The victim was rushed to Gwalior, and tests in a hospital confirmed rape, police sources said.

Twenty people have been detained as suspects and are being questioned, Chambal Range Deputy Inspector General of Police D.K. Arya was told Zee News.

The Swiss Embassy called for a speedy probe into the incident and has been in touch with authorities in Madhya Pradesh.

Swiss Ambassador Linus von Castelmur spoke to the woman and assured her of all help.

"The embassy is most distressed with the gang-rape of a Swiss national in Madhya Pradesh. The ambassador has been able to speak to the victim and her partner and has assured them of all possible support. Their health and treatment is the priority of the moment,” the embassy said in a statement.

"The embassy has also been in touch with the local authorities and has requested for swift investigation and for justice to be done," the statement said.

The incident comes three months after the gruesome gang-rape and murder of a woman in the capital in December, which sparked massive protests across India.

The prime suspect in the case was found dead March 11 in New Delhi’s Tihar Jail. Authorities have launched an investigation into the death, while the rape trial continues on a fast track court in New Delhi.