WASHINGTON — Members of Congress have been told in confidential briefings that Pakistan is rapidly adding to its nuclear arsenal even while racked by insurgency, raising questions on Capitol Hill about whether billions of dollars in proposed military aid might be diverted to Pakistan's nuclear program.
Adm. Mike Mullen, the chairman of the Joint Chief of Staffs, confirmed the assessment of the expanded arsenal in a one-word answer to a question on Thursday in the midst of lengthy Senate testimony. Sitting beside Defense Secretary Robert Gates, he was asked whether he had seen evidence of an increase in the size of the Pakistani nuclear arsenal.
"Yes," he said quickly, adding nothing, clearly cognizant of Pakistan's sensitivity to any discussion about the country's nuclear strategy or security.
Inside the Obama administration, some officials say, Pakistan's drive to spend heavily on new nuclear arms has been a source of growing concern. The country is producing more nuclear material at a time when Washington is increasingly focused on trying to assure the security of an arsenal of 80 to 100 weapons so that they will never fall into the hands of Islamic insurgents.
The administration's effort is complicated by Pakistan's production of an unknown amount of new bomb-grade uranium and, once a series of reactors is completed, bomb-grade plutonium for a new generation of weapons.
President Barack Obama has called for passage of a treaty that would halt all nations from producing more fissile material — the hardest part of making a nuclear weapon — but so far has said nothing in public about Pakistan's activities.
Obama administration officials said they told Congress that their intent was to assure that military aid to Pakistan was directed toward counterterrorism and not diverted. But Mullen's public confirmation that the arsenal was increasing — a view widely held in both classified and unclassified analyses — seemed certain to aggravate Congress' discomfort.
Senior members of Congress already were pressing for assurances from Islamabad that the American military assistance would be used to fight the insurgency — and not be siphoned off for more conventional military programs to counter Pakistan's historic adversary, India.
Official confirmation that Pakistan has accelerated expansion of its nuclear program only added to the consternation of those in Congress already voicing serious concern about the security of those warheads.
At the State Department, senior officials warned against a spillover of concerns over Pakistan's nuclear program to the debate on new civilian assistance.
"It is in our national interest to help Pakistan deal with the growing instability within its borders," said Ian Kelly, a State Department spokesman. "Instability is a threat to Pakistan and potentially a threat to its neighbors and the United States."