Signs Stir Concern North Korea Might Test Nuclear Bomb

Diplomat in Asia to Confer With Officials

U.S. officials are increasingly concerned that North Korea may be preparing its first test of a nuclear weapon, though they warn that the information is sketchy and not definitive.

A top U.S. diplomat, Assistant Secretary of State Christopher R. Hill, flew to the region yesterday to consult over the weekend with officials in Beijing, Tokyo and Seoul about the signs that a test may be in the works. Officials especially want China, North Korea's main patron, to use its leverage with Pyongyang to stop it from conducting a test.

Since withdrawing from nuclear disarmament talks two months ago, Pyongyang has declared that it has nuclear weapons and has made increasingly provocative announcements. Recently, it said it would strengthen its nuclear arsenal, citing the need to counter what it called hostile U.S. policy.

One U.S. official said the concern about Pyongyang's intentions was heightened by signs of increased activity at missile sites and other places that could be used for underground tests. U.S. spy satellites observed the activity, but it is extremely difficult to interpret, as the mistakes regarding alleged weapons of mass destruction in Iraq demonstrated.

"We see these things," he said, speaking on the condition of anonymity because he was discussing intelligence matters. "But much of what we see is open to interpretation."

The Wall Street Journal first reported yesterday in its online edition that North Korea may be preparing a test, sending stocks tumbling and oil prices soaring.

North Korea also shut down its nuclear facility at Yongbyon about 10 days ago, indicating that it may be preparing to remove nuclear-fuel rods so the weapons-grade plutonium inside the rods can be extracted. U.S. intelligence analysts believe that North Korea reprocessed enough plutonium two years ago for as many as half a dozen weapons.

But there is a strong debate within the administration about whether North Korea would actually detonate a nuclear bomb. Since the impasse over North Korea's nuclear ambitions began in 2002, China has been able to maintain that there is no definitive proof that North Korea has such weapons. A test would shatter that diplomatic ambiguity and make it more difficult for China to block sanctions at the United Nations.

"It would take them off the edge," another U.S. official said.

But other officials believe North Korea has concluded that a nuclear test would be the only way to convince the world that it has joined the nuclear club. Although many nations would condemn the test, North Korea may have concluded that the consequences would eventually fade away. The administration, for instance, recently decided to restart F-16 fighter-jet sales to Pakistan, which were suspended 15 years ago because of that country's illicit nuclear activities.

U.S. analysts had previously detected signs of a possible test, but none has occurred. North Korea is known to enjoy putting on a show for U.S. spy satellites. Two years ago, Pyongyang laid out missiles near a parade route so they could be seen by satellites, but it did not display them publicly during the parade to avoid riling diplomatic sensitivities.