UPDATE!!!! Desperate battle to defuse collar bomb hung round neck of girl, 18, 'being held to ransom' at multi-million pound mansion: Video

* Balaclava-clad intruder 'broke in and attached bomb and note to girl'
* Shaken parents outside house haven't spoke to their daughter yet

* Family is one of Sydney's wealthiest with mansion in exclusive street

* Bomb officers investigating other 'items' in house

* 'Life of young girl potentially at risk', say police
* Bomb is proving a 'tough nut to crack'

Four bomb squad officers have entered a house in a wealthy suburb of Sydney where a terrified teenage girl has had an explosive device strapped to her body by a balaclava-clad intruder.

Police said a 'delicate operation' was taking place in a property in the suburb of Mosman where wealthy families including bankers, stockbrokers, sports personalities and company directors live.

A senior police officer described the device as an unusual 'collar bomb', which has never been seen before in Australia, but an exact description has yet to be officially given.

Read more: http://www.dailymail.co.uk/news/article-2021874/Teenage-girl-mansion-Australia-bomb-ransom-note-strapped-her.html#ixzz1TyJQqOun
Update!!!!!!!!!!5:10 New York Time

After 10 hours, police in a wealthy suburb of Sydney released a teenager involved in a bomb scare. Police refused to confirm media reports that the teenager had been strapped to an explosive device in an apparent extortion attempt.
Update at 3:30 p.m. ET: Assistant Police Commissioner Mark Murdoch said the British armed forces were contacted, because they had experience with the device, described as a collar bomb, The Australian  says. Police reportedly have X-rayed the intact device and are analyzing its components before attempting to defuse it.
Murdoch said the 18-year-old girl, Madeleine Pulver, was kept in an "uncomfortable position" during the ordeal and was taken to hospital for evaluation early Thursday,The Daily Telegraph reports.

Madaline Pulver 18 year old