The potential for nuclear staff or soldiers with militant sympathies to collude in a Taliban or al-Qaeda attack was a cause for greater concern, he said. The army has been Islamicised in the past and has senior officers who are known to be anti-Western and anti-American. "No screening programme will ever be able to weed out all Islamist sympathisers or anti-Westerners among Pakistan's military or civilians with nuclear weapons expertise," he said.