"Pakistan's nuclear weapons continue to grow. We are concerned that this growth, as well as the evolving doctrine associated with tactical weapons, increase the risk of an incident or accident," Defence Intelligence Agency Director Vincent Stewart told the Senate Armed Services Committee.
"Islamabad continues to take steps to improve its nuclear security, and is aware of the threat presented by extremists to its programmes," Stewart said in his testimony yesterday.
A Congressional report in January had estimated Pakistan's nuclear warheads to be between 110 and 130 and said that they are aimed at deterring India from taking military action against it. The report on 'Pakistani nuclear forces 2015' by the Bulletin of Atomic Scientists had estimated that if the country continues to enrich its nuclear arsenal with the present speed, it will have 220 to 250 warheads by 2025.
The 2015 report, authored by Hans M Kristensen and Robert S Norris, said the two key factors will be how many nuclear-capable launchers Pakistan plans to deploy, and how much India's nuclear arsenal grows
Meanwhile, Stewart further said that Pakistan will face internal security threats from militants and separatist groups this year. Islamic State's branch in Afghanistan-Pakistan and al-Qaeda in the Indian subcontinent will remain significant security concerns for Islamabad, he said.
"Counterinsurgency operations along Pakistan's Western border and paramilitary operations in Karachi have had some success in reducing violence and are likely to continue," Stewart said.
(With PTI inputs)