NEW DELHI: US secretary of state Hillary Clinton raised the ultimate scare this weekend saying the "unthinkable" could actually happen in Pakistan — that the Taliban and Al Qaeda could topple the government, giving them "the keys to the nuclear arsenal". In an interview in Baghdad, she said the US would not "let this go on any further, which is why we're pushing so hard for the Pakistanis to come together around a strategy to take their country back". Clinton's statement raised eyebrows in India, because it came just a few days after Prime Minister Manmohan Singh declared, at an election rally, that he had been "assured" that Pakistan's nuclear weapons were safe. Singh's announcement came as a response to BJP's concerns on the issue. He said, "We have been assured that Pakistan's nuclear weapons are in safe hands as of now. And I have no reason to disbelieve the assurance." Although he did not name the source of his assurance, its clear that it would have to be the US at a very high level. The PM had recently met US President Barack Obama in London and officials said Pakistan was very much part of the discussions. Besides, as Indian officials say, apart from Pakistan, the US is the only country that has close to intimate knowledge of Pakistan's nuclear weapons. Indian officials say whenever India has asked the US about the security of Pakistan's N-arsenal, the US confidently reassures them that the weapons are "safe". In fact, Mike Mullen, chairman of the joint chiefs of staff, had said not long ago that he was "reasonably confident that the nuclear weapons were secure". But on Saturday, Clinton said the danger was that the weapons were "dispersed" all over the country. The explanation could be either that the US had been banking on certain Pakistani assurances which may be cracking in a test of credibility, or that she was saying this now to scare other countries into mounting even greater pressure on Pakistan. Former foreign secretary Kanwal Sibal said, "If the comment originated from the possibility that the arrangements the US had made to secure those weapons were now vulnerable, that would be of greater concern." The concern has never been that the Taliban or Al Qaeda would take over the weapons and fire them off. That will not be possible, because the warheads are de-coupled from the trigger devices. Chaklala, Sargodha, Quetta and Karachi are where they are stored. According to reports in 2002, Washington supplied Pakistan `permissive action links' (PAL) locks worth $100 million, to prevent tampering with these weapons. Pakistan's Nuclear Command Authority and Strategic Plans Division manage its nuclear arsenal. What is worrisome, say officials, is that a radicalised Pakistani army officer or nuclear scientists could do the trick. That's why the radicalisation of Pakistan is a global concern. Rand Corporation's security expert Brian Michael Jenkins said in an interview, "There is concern that if there is a radical takeover of Pakistan itself, the armed forces will behave like the Iranian forces and simply say `this is the new government, we are part of the new government' and therefore the nuclear arsenal could become part of a more radical government."