A Swiss woman has been gang-raped by a group of men in the central Indian state of Madhya Pradesh, police say.

The woman was camping with her husband at a village in Datia district on Friday during a cycling trip when they were attacked by eight to 10 men.

The assailants overpowered the husband before gang-raping his wife.

More than 20 people have been detained in connection with the attack, which has led the Swiss embassy to demand a thorough investigation.

The BBC's Salman Ravi reports from Raipur, in central India.