Police in central India said Sunday that they have detained 20 men in connection to the gang rape of a Swiss woman on a cycling and camping trip with her husband.

The attack took place Friday night in the central state of Madhya Pradesh, police said on Saturday.

The attackers "tied up the man and raped the woman in his presence," local police official S.M. Afzal told the news agency AFP, adding they stole money, a laptop and a mobile phone from the pair. He said they had "put up a tent to stay overnight" in a forested area.

The woman was treated in a nearby hospital, led by police with her face concealed with a hood. This is common practice in India, where rape victims by law cannot be identified to protect them from the stigma attached to rape.

Indian television showed dozens of police searching the forest where the attack occurred.

The Swiss foreign ministry said diplomats were assisting the couple and were in contact with local authorities.

"We are deeply shocked by this tragic incident suffered by a Swiss citizen and her partner in India," the ministry in Bern said in a statement, adding that it hoped the attackers would be "swiftly identified and would appear before a court to answer for their actions."

In travel advice released last month, Switzerland warned its citizens about an increasing number of rapes and sexual assaults in India.

A familiar, shocking story

The attack comes just three months after the fatal gang rape of a 23-year-old physiotherapy student in the capital New Delhi, which sparked nationwide protests and demands for the government to better treat and protect women.

The victim and her male friend were attacked after boarding a bus on December 16, 2012, as they tried to make their way home after seeing a movie. The two were dumped along the side of the road. The woman later died in hospital in Singapore.

Six suspects, the only passengers on the private bus, are accused of beating the man with a metal bar before raping the woman and using the bar to inflict massive internal injuries to her, police say.

Last week, the alleged driver of the bus, Ram Singh, reportedly hung himself in jail.

According to India's National Crime Records Bureau, one woman is raped every 20 minutes in India, but most go unreported.

jr/jlw (AP, AFP, Reuters, PTI)