Australian police say bomb squad officers are working to dismantle a suspicious device strapped to a young woman in Sydney.

Police declined to confirm local reports that a “collar bomb” has been strapped to the 18-year-old woman, who called police to a house in an exclusive Sydney neighborhood Wednesday afternoon. But a police spokesman has confirmed that the young woman is unable to get away from the device.

Australian television, quoting local media, said a ransom note was attached to the woman's neck. The report also said the unidentified victim belongs to one of Sydney's wealthiest families.

Police said the woman and a bomb squad remained in the house seven hours after the first call for help, and that she was doing her best to assist police. A spokesman described the process of dismantling the device as “very delicate.”

Streets have been closed off around the house, in a neighborhood filled with multi-million dollar mansions.