US wary of human bomb implants on planes

The United States is monitoring the possibility of terror groups trying to down aircraft by implanting explosives in the human body, Homeland Security chief Janet Napolitano said on Wednesday. Napolitano stressed that there was no evidence of an imminent threat from a so-called \"body bomb\", but said the prospect was one of the ever-changing attack strategies that security officials had to combat. She cited the case of Nigerian \"underwear bomber\" Umar Farouk Abdulmutallab, who tried to blow up an airliner in 2009 with explosives hidden in his pants, as an example of the innovations adopted by militants. \"It is fair to say that there are a number of ways our adversaries have explored to get explosives aboard airplanes, such as the underwear bomber,\" she told reporters in New Zealand. \"Another, of course... is actually implanting explosives inside an individual. \"Do we have specific, credible evidence of a threat today? I would not say that we do. However, the importance is that we all lean forward and that, as people are travelling, we are sensitive to the ever-evolving threats that we see.\" Napolitano, in Wellington to sign an information-sharing agreement with New Zealand, did not specify what measures were being taken to monitor for surgically implanted bombs. \"We\'re always making changes, part of what we do is predictable unpredictability,\" she said. \"We don\'t want our adversaries to be able to predict exactly the kinds of measures that they will see in any given airport at any given time.\" Underwear bomber Abdulmutallab managed to smuggle more than 76 grammes of the explosive Pentaerythritol tetranitrate (PETN) on board a Detroit-bound Northwest Airlines flight from Amsterdam on Christmas Day in 2009. But the Al-Qaeda plot failed when the bomb did not detonate properly, instead causing a fire as the plane began its descent to Detroit. Passengers and crew members were able to restrain Abdulmutallab and extinguish the blaze, allowing pilots to safely land the plane. He was handed four life sentences and an additional 50 years behind bars in February. Napolitano said the case demonstrated the global nature of the threat. \"There were people from 17 countries aboard that plane who would have perished if he had successfully detonated the PETN aboard the flight,\" she said. \"So this is indeed an international problem and that is why these international agreements and international interactions are ever more important in today\'s world than perhaps any time in our history.\"