WASHINGTON - Although intelligence analysts are increasingly concerned that North Korea may be able to arm a missile with a nuclear warhead, U.S. spy agencies have not obtained evidence confirming that Pyongyang has developed that capability, intelligence officials and weapons proliferation experts said last week.
The officials said that assessments of North Korea's ability to devise a functional nuclear warhead are based largely on projections of its presumed progress toward that goal, not on any significant intelligence discoveries.
For that reason, several officials said that a senior Pentagon intelligence official may have overstated the position of analysts when he told a Senate committee Thursday that U.S. intelligence believes North Korea has the ability to arm a missile with a nuclear device.
That assertion by Vice Adm. Lowell E. Jacoby, head of the Defense Intelligence Agency, appeared to mark the first time that a senior government official had declared North Korea capable of making a nuclear warhead.
Pentagon officials sought to play down Jacoby's remarks. Pentagon spokesman Lawrence Di Rita stressed that there had been "no new assessment" on the North Korean nuclear threat. He also said the United States could not be sure that North Korea had the ability to arm a ballistic missile and hit U.S. targets.
"I don't believe we know that," Di Rita said at a news conference, stressing that Jacoby was largely describing theoretical capabilities. Di Rita declined to say whether Jacoby had misspoken. "His words were what his words were," Di Rita said.
In a follow-up statement Friday evening, Pentagon spokesman Bryan Whitman said: "North Korea has a theoretical capability to produce a warhead and mate it with a missile, but we have no information to suggest they have done so."
Jacoby's comments alarmed lawmakers and suggested a significant escalation in the North Korea nuclear threat.
His remarks also came as joint diplomatic efforts by China, the United States, Russia, Japan and South Korea to persuade North Korea to dismantle its nuclear weapons program have stalled.
In Seoul, South Korea, U.S. Assistant Secretary of State Christopher Hill said that "the mood as we discuss the progress of these talks is not very good."
Hill has been shuttling among Seoul, Beijing and Tokyo and said he plans a trip to Moscow shortly.
The North has not responded to President Bush's characterization Thursday of North Korean leader Kim Jong Il as a "tyrant" and a "dangerous person."
Hill urged the North Koreans not to overreact. Bush has "made it very clear we are looking for a diplomatic solution," he said.
In Washington, some government officials said Jacoby was too categorical when he told the Senate Armed Services Committee that U.S. intelligence has assessed that North Korea is capable of putting a nuclear payload on a missile.
"He went beyond what the intelligence community consensus is," said a government official with access to U.S. assessments on North Korea.
The ability to arm a missile with a nuclear payload "is something you have to worry about and assume they're working on," the official said. "But that's not something you see from overhead imagery. You need other kinds of intelligence to make the determination they've actually accomplished that engineering feat."
Several officials acknowledged that the United States lacks such intelligence.
A U.S. intelligence official said there are "differing views on where [the North Koreans] are" in developing nuclear warhead technology.
In February, North Korea declared publicly that it had nuclear weapons. But the ability to "marry" a nuclear device with a ballistic missile requires significant technological expertise, including "miniaturizing" the device to fit inside a missile tip.
Other experts expressed more skepticism that North Korea is as far along as Jacoby suggested.
"I think he misspoke," said Joseph Cirincione, a nuclear proliferation expert at the Carnegie Endowment for International Peace. "North Korea does not have a missile that can reach the United States. There is no compelling evidence that they have a nuclear warhead that can be put on any missile."
The Los Angeles Times is a Tribune Publishing newspaper.