Pakistan insists smaller weapons would deter a sudden attack by its bigger neighbour India, which is also a nuclear power. But the United States worries tactical weapons may further destabilise an already volatile region because their smaller size makes them more tempting to use in a conventional war.
Sharif and Obama are due to meet at the White House today. The Obama administration is preparing to sell eight F-16 fighter jets to Pakistan in an attempt to bolster the two countries' relationship despite Washington's concerns about Pakistan's growing nuclear arsenal, according to a US source familiar with the matter.
The aircraft sales, which the US Congress could block, would be a symbolic step given Pakistan's already large fleet of fighter jets. The sales were first reported by the New York Times.
The United States wants Pakistan to commit to not using tactical nuclear weapons but Islamabad wants to keep its options open as a way of deterring a potential Indian attack, said Maria Sultan, head of the South Asian Strategic Stability Institute.
Pakistan says the United States is demanding unreasonable limits on its use of nuclear weapons and not offering much in return apart from a hazy promise to consider Pakistan as a recognised recipient of nuclear technology.
US Secretary of State John Kerry met Sharif on Wednesday but State Department spokesman John Kirby declined to say whether a US call for nuclear restraint was discussed.


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