Updated

North Korea's Asian neighbors expressed surprise and anger Thursday at a White House announcement the communist country has admitted it is developing nuclear weapons.

The news was particularly startling because it came after a series of signs that North Korea's enigmatic ruling regime, pressured by food shortages and a barely functioning economy, was taking a softer, more open stance toward its relations with the outside world.

Concerns were highest in South Korea and Japan, which have been actively pursuing closer relations with their secretive and often hostile communist neighbor.

"Japan is gravely concerned about the U.S. announcement North Korea is developing nuclear weapons," Prime Minister Junichiro Koizumi's spokeswoman, Misako Kaji, said Thursday.

She said Koizumi "will continue to press the North Korea strongly on this matter."

In Seoul, Deputy Foreign Minister Lee Tae-sik urged the North to abide by international anti-nuclear agreements. But he also called for continued dialogue with all concerned, and said South Korea would raise the issue in a round of Cabinet-level talks between the Koreas scheduled for Oct. 19-22 in Pyongyang.

"All these issues should be resolved through dialogue and peacefully, and we will continue to strengthen cooperative consultations with the United States and Japan," Lee said.

South Korea has consistently pursued the de-nuclearization of the Korean Peninsula in line with international agreements, including the Treaty on the Non-Proliferation of Nuclear Weapons and the 1994 Agreed Framework between North Korea and the United States.

The White House confirmed late Wednesday that North Korea has told the United States it has a secret nuclear weapons program in violation of an agreement signed with the previous U.S. government under President Clinton.

North Korea also told U.S. diplomats it is no longer beholden to the anti-nuclear agreement, said a senior U.S. official who spoke on condition of anonymity.

The disclosure complicates Bush's campaign to disarm Iraq under threat of military force, coming almost nine months after Bush said North Korea was part of an "axis of evil" along with Iran and Iraq.

"We seek a peaceful resolution of this situation," said White House spokesman Sean McCormack. "Everyone in the region has a stake in this issue and no peaceful nation wants to see a nuclear-armed North Korea."

A senior U.S. official was to travel to Japan and South Korea for consultations soon.

North Korea had no immediate response.

The news put Tokyo in a particularly delicate position.

In an unprecedented summit with North Korean leader Kim Jong Il on Sept. 17, Prime Minister Junichiro Koizumi has vowed to push ahead with talks to establish formal diplomatic ties. Both sides are scheduled to meet in Kuala Lumpur, Malaysia, on Oct. 29-30.

The resumption of talks was made possible by Kim's confession that elements in the military kidnapped more than a dozen Japanese in the 1970s and 80s. The five known survivors are currently in Japan for brief visits, their first homecoming in nearly 25 years.

Though Koizumi's support ratings shot up immediately after the summit, public outrage has since swelled as more details have emerged about the deaths of at least eight of the abduction victims.

Polls indicate most Japanese now think it is too early to normalize relations, and the North's secret development of nuclear weapons would likely increase such concerns in a country where anti-nuclear sentiment runs especially deep.

With the bombings of Hiroshima and Nagasaki during World War II in 1945, Japan is the only country to have been attacked with nuclear weapons.