The United States officials have rejected a claim by a private arms-control group that a new reactor, being built in Khushab, is unusually large and could make fuel for up to 50 nuclear warheads a year, according to The New York Times report on Thursday.
"We have consulted with our experts and believe the analysis is wrong," US National Security Council spokesman Frederick Jones, was quoted as saying. "The reactor is expected to be substantially smaller and less capable than reported," he said.
The report last week by the private group came amid debate over the Bush administration's proposed nuclear deal with India, giving rise to speculation that Pakistan was trying to speed ahead in a South Asian arms race.
The Times said the group's experts on Wednesday stood by their report, which is based mainly on the examination of commercial satellite images of the half-built reactor.
But in interviews with the Times, the US officials set the record straight about the reactor. They said their own intelligence indicated that the emerging reactor appeared to be roughly the same size as the small one Pakistan currently used to make plutonium for its nuclear programme, and said the new model might be intended to replace the old one.
It said the officials spoke on the condition of anonymity because of prohibitions on the public discussion of secretive intelligence issues. "This has been looked at for a long time and hasn't generated a lot of hand-wringing," an unnamed senior intelligence official was quoted as saying of the new reactor. "It could be a replacement."
The Times wrote: "The episode underscores the uncertainties that often surround nuclear intelligence. In recent years, the government has come under fire for warnings of nuclear dangers that have turned out to be false, most notably in the case of Iraq's efforts. Critics say the analyses are often subject to political spin," he said.
Pakistan is a major ally of the United States in its effort to prevent terrorism. But the report said the United States also closely monitors Pakistan's nuclear work.
The reactor issue began on July 24 when the Institute for Science and International Security, based in Washington, issued a report publicly disclosing the reactor's existence and estimating that when completed, it would be quite powerful - about 1,000 megawatts. That would be a 20-fold increase over Pakistan's current plutonium reactor, which arms analysts estimate at 40 to 50 megawatts and able to make fuel for about two warheads a year.
The group's paper, first reported in the Washington Post, contained many caveats, including that its estimate of the new reactor's power 'remains uncertain.' Institute for Science and International Security President David Albright defended the accuracy of his group's report, and noted the Bush administration's poor record on nuclear intelligence.