Bush: Going nuclear will 'alienate' North Korea
N. Korea repeats treaty call
CRAWFORD, Texas (CNN) -- President Bush said Monday the United States will continue working with "the neighborhood" to convince North Korea that building nuclear weapons would "alienate" the secretive communist state from the rest of the world.
U.S. officials suspect North Korea may be operating a secret nuclear weapons facility in addition to its known nuclear site at Yongbyon, a senior U.S. defense official told CNN.
Bush said he believes a diplomatic solution to the North Korean nuclear standoff can be reached if North Korea's neighbors tell the government of Kim Jong Il, "A decision to develop a nuclear arsenal is one that will alienate you from the rest of the world."
The Bush administration has refused to engage in direct talks with North Korea about its nuclear program, but has tried to engage Pyongyang through other countries in the region -- Russia, China, Japan and South Korea.
"We must continue to work with the neighborhood to convince Kim Jong Il that his decision is an unwise decision, and we will do just that," Bush said.
U.S. officials say they believe North Korea has one to three nuclear weapons.
Air sensors on North Korea's borders have detected elevated levels of krypton 85, a gas emitted in the processing of spent nuclear fuel rods into weapons-grade plutonium.
But the gas appeared not to be emanating from North Korea's known Yongbyon nuclear plant site, indicating the possibility of a second site, the official said.
If North Korea's estimated 8,000 nuclear fuel rods are reprocessed for plutonium, U.S. officials say, Pyongyang may be able to produce six to 12 additional nuclear warheads.
"North Korea has no legitimate use for plutonium harvested during this procedure," White House spokesman Scott McClellan said. "Reprocessing to recover plutonium is a clear indication that North Korea is seeking to enlarge its nuclear arsenal."
'Cold water on our economy'
While not ruling out its existence, South Korea played down the reports of a secret nuclear facility.
President Roh Moo-hyun "expressed concern about the phenomenon of unclear and groundless media reports throwing cold water on our economy," Kim Man-soo, a deputy spokesman of the presidential Blue House said on Monday.
South Korean Deputy Foreign Minister Lee Soo-Hyuck said he doubted the reports of a secret facility would sway "the firm U.S. position of seeking a peaceful and diplomatic solution" to the nuclear standoff between Pyongyang and Washington that began in October.
"There is no conclusive information about such facilities," he told a domestic radio program.
The U.S. official told CNN that although computer analyses tracking the krypton 85 as well as other evidence suggest such a site, no other solid information exists, including satellite reconnaissance.
The gas "could be coming from somewhere other than Yongbyon," the official said, but "we're just not sure." He said the scientific method used was "not precise."
The official acknowledged North Korea has been digging a number of deep underground facilities in mountainous areas over the past several years but could not confirm if these sites might be the location of a nuclear facility.
Though North Korea has not yet responded to the reports, Pyongyang on Monday reissued its demand for a non-aggression treaty with the United States.
A commentary by North Korea's state-run Korean Central News Agency said talks based on "fairness, equality and trust" were the only way to resolve the nuclear crisis.
Russia has urged the United States and North Korea to start talks as soon as possible to avoid escalating the standoff.
The New York Times reported on Sunday that U.S. officials have long thought North Korea might try to build another plant in case of a U.S. airstrike.
A suspected underground site was inspected five years ago at U.S. insistence, but it was found empty, the Times reported.
McClellan would not confirm the report. "We do not discuss intelligence matters," he said.
But he noted the North Koreans have taken "a number of escalating steps in recent months," including expelling international nuclear inspectors, restarting nuclear facilities and announcing in April that they would develop a nuclear weapons program.
North Korea recently told the United States it had finished processing 8,000 spent fuel rods into plutonium and intends to build nuclear weapons.
U.S. officials said they are "very concerned" about the claim, and while they have evidence North Korea is reprocessing some of the spent fuel rods, they can't say how many.
North Korea also has an advanced ballistic missile capability that could potentially be able to deliver a nuclear warhead over a long distance.
CNN's Chris Plante contributed to this report.