PAKISTAN:PAKISTANI PRESIDENT Pervez Musharraf's resignation earlier this week raises questions about the continuing security of the country's nuclear arsenal, over which he presided as head of the National Command Authority (NCA).
It is presumed the "nuclear button" or codes authorising the eventual release of Pakistan's atomic weapons have been passed on to acting president Mohammed Mian Soomro, the chairman of the upper house of parliament.
Technically, Mr Soomro now heads the 10-member NCA committee that Mr Musharraf established in 2000 to manage the country's stockpile of 60 to 65 atomic warheads.
Earlier this year, following a spate of suicide bombings by jihadists and the assassination of former prime minister Benazir Bhutto, the Musharraf-led administration went to great lengths to reassure the international community its nuclear assets were safe from seizure by Islamic fundamentalist groups.
In an unprecedented briefing, retired Lieut Gen Khalid Kidwai, head of the crucial Strategic Plans Division, told journalists Islamabad deployed 10,000 soldiers to keep the atomic weapons safe.
He said there was "no conceivable scenario" in which al-Qaeda or associated Taliban cadres could seize power and asserted that Pakistan's nuclear weapons, fissile material and related infrastructure were "absolutely safe and secure".
The location of Pakistan's nuclear arms remains a secret, but western intelligence sources believe they are located near Islamabad, with the warheads and delivery systems separated.
But analysts and military planners are worried, as Islamabad's record on nuclear proliferation is, at best, dubious. Its top atomic scientist, Dr Abdul Qadeer Khan, was exposed in 2004 as the head of an international black market operation in nuclear technology, working reportedly in collusion with the military, which leaked nuclear secrets to Iran, Libya and North Korea.
Pakistani nuclear scientists are even believed to have travelled to Afghanistan to meet the al-Qaeda leadership when the Taliban controlled Kabul before being ousted by the US-led coalition in 2001.
These fears have persisted as al-Qaeda and Taliban militants gained a firm foothold along the lawless northwestern frontier with Afghanistan. Pakistan has also struggled to dispel suspicions that elements in its intelligence services have extremist sympathies.