Oct. 3 (Bloomberg) -- North Korea's government today said the country will conduct its first nuclear test, a move the U.S. warned would ``pose an unacceptable threat'' to the world.

North Korea ``will in the future conduct a nuclear test under the condition where safety is firmly guaranteed,'' the Foreign Ministry said in a statement carried by the official Korea Central News Agency, without giving a date for the test. The U.S.'s ``increasing threat of a nuclear war and its vicious sanctions and pressure have caused a grave situation on the Korean Peninsula,'' the ministry said.

State Department spokesman Sean McCormack said the U.S. ``will continue to work with its allies and partners to discourage such a reckless action and will respond appropriately.'' Japanese Prime Minister Shinzo Abe said such a test would be ``unforgivable'' and require a severe international response.

The U.S. and Japan have been joined by South Korea, China and Russia in talks with North Korea aimed at getting the communist nation to scrap its nuclear program. The negotiations have coincided with a nuclear dispute involving Iran, which has defied United Nations' demands to end uranium enrichment.

South Korea, in response to the statement from its neighbor, said it was raising its security level, the Associated Press cited the Presidential Office in Seoul as saying.

Abe's Comments

Abe, speaking to reporters in Tokyo, said he doesn't know whether North Korea will conduct such a test and said Japan would analyze the report and liaise with the U.S. government.

North Korea announced on Feb. 10 last year it had made nuclear weapons after extracting plutonium by reprocessing spent nuclear fuel rods from power plants.

North Korea may have produced as many as six nuclear weapons from spent fuel, U.S. officials estimated in 2004, according to a Congressional Research Service report on the country's atomic arms program dated May 25 this year.

A report by the Institute for Science and International Security on June 26 said North Korea may have enough plutonium to make as many as 13 nuclear weapons.

North Korea's announcement came on Korea's National Foundation Day, which marks the start of the 5,000-year-old Chosun dynasty, and a day after South Korean Foreign Minister Ban Ki Moon won the fourth and final straw poll to become the next UN secretary general. An official vote is scheduled for Oct. 9.

`Unpredictable'

``I never bet money on what the North Koreans might do because they're completely unpredictable,'' said Jon Wolfsthal, who monitored the North Korean program for the U.S. Energy Department a decade ago. ``But they have made preparations, and now they've made a statement, which makes it harder for them not to conduct a test because they're starting to put political capital behind this.''

The North Koreans are also ``much more likely to conduct a nuclear test now than they were six years ago,'' when they were complying with international monitors, said Wolfsthal who is now a fellow at the Center for Strategic and International Studies in Washington.

McCormack, speaking to reporters in Cairo during a visit by Secretary of State Condoleezza Rice, said the test ``would pose an unacceptable threat to Asia and the world.''

Rice, at a press conference later, said the test would be a ``very provocative act'' and ``an issue for the entire neighborhood.''

U.S. Ambassador to the United Nations John Bolton said the Security Council would meet tomorrow to seek a ``coherent policy'' on North Korea. He said the U.S. didn't press for a reaction today because the panel adopted a resolution on July 15 telling North Korea to suspend its nuclear program.

``North Korea should not take that silence as acquiescence,'' Bolton told reporters at the UN.

China, Russia

Chinese Ambassador Wang Guangya, while saying his government wouldn't ``welcome'' a nuclear test, said the six- party talks were a better venue in which to discuss the issue. ``I urge all sides to exercise restraint,'' he said.

Russian Foreign Minister Sergei Lavrov, speaking in Moscow, said his government hopes the six-nation talks between the two Koreas, Russia, China, Japan and the U.S. resume soon, while declining to comment specifically on the North's announcement.

The South Korean Defense Ministry declined to comment on the statement. Officials at South Korea's Presidential Office and the Foreign Ministry weren't immediately available for comment.

North Korea agreed in principle on Sept. 19 last year to abandon its nuclear weapons program. The North agreed to work toward a final agreement to halt all nuclear programs in return for energy and food assistance along with security guarantees.

A follow-up round of talks among the six nations to work on the details of the September accord ended without agreement in November, raising concerns about North Korea's commitment to a nuclear-free Korean peninsula.

To contact the reporter for this story: Kevin Cho in Seoul at kcho2@bloomberg.net

Last Updated: October 3, 2006 15:54 EDT