North Korea faced stern warnings from its neighbors Wednesday against carrying out an unprecedented nuclear test, but insisted the move wasn't meant to be a provocation. A top South Korean official said there was no sign a test was imminent.
China, Japan and South Korea all announced separate one-on-one summits among their leaders next week, ratcheting up diplomacy over tensions caused by the North's announcement Tuesday that it intends to conduct a test.
Such a test would confirm the North's claim that it has atomic weapons, and would severely undermine efforts to prevent an Asian nuclear arms race by getting Pyongyang to disarm.
South Korea's top official on dealings with the North, Unification Minister Lee Jong-seok, said Wednesday that there were no definite signs that the test is imminent.
Japan's Asahi newspaper reported Wednesday, citing unidentified government sources, that two Japanese spy satellites had not observed any activities to suggest preparations for a nuclear test at a suspected underground site in the North.
However, Lee also told lawmakers there was "a high possibility" a test would eventually take place if "efforts to resume the six-party talks fail."
North Korea has boycotted six-nation nuclear talks _ which also involve China, Japan, Russia, South Korea and the U.S. _ for nearly a year, angered by U.S. financial restrictions imposed over the North's alleged illegal activities such as money laundering and counterfeiting.
But South Korean Defense Minister Yoon Kwang-ung said it was "difficult to monitor activity in case of an underground nuclear test," noting Seoul was cooperating on surveillance with the U.S.
Meanwhile, an official at the North's embassy in Australia, Pak Myong-guk, said Wednesday that Pyongyang's planned nuclear test "is not provocative."
"It is just the corresponding measure for defense, for us to defend ourselves," Pak told The Associated Press. "It is the really essential process for nuclear deterrent."
The North often insists it needs nuclear weapons to deter a U.S. attack.
China _ North Korea's main ally and key benefactor _ appealed Wednesday for calm and restraint in an unusually pointed statement that referred directly to North Korea by name. The statement contrasted with earlier Chinese responses, which have typically appealed to all sides without naming countries.
"We hope the North Korean side will be sure to keep calm and restrained on the nuclear test issue," said Foreign Ministry spokesman Liu Jianchao in a statement on the ministry Web site.
South Korea's President Roh Moo-hyun called Wednesday for a "cool-headed and stern" response to the North's announcement, while Foreign Ministry spokesman Choo Kyu-ho said a nuclear test by North Korea could cause a change in its engagement policy toward the communist regime.
"If North Korea pushes ahead with a nuclear test, North Korea should take full responsibility for all consequences," Choo said after an emergency meeting of South Korean security ministers.
Asked to elaborate on what the consequences would be, Choo said a North Korean nuclear test could bring about a "shift" in Seoul's engagement policy toward the North, but also stressed that doesn't mean abandoning that policy altogether.
South Korea has consistently pursued dialogue with North Korea since their leaders met in a historic summit in 2000, leading to a rift with Washington that favors a harder line toward the communist regime.
Seoul is one of the main aid providers to the impoverished North, but it suspended regular relief shipments after the North test-fired a series of missiles in July over international objections, drawing U.N. Security Council condemnation. However, the South later agreed to send emergency aid to help the North cope with massive floods that struck the country in mid-July.
Despite the test threat, the South on Wednesday shipped previously promised aid, including 6,400 tons of cement to the North, the South's Unification Ministry said.
"As North Korea has yet to conduct a nuclear test, it is difficult to immediately halt sending flood relief aid, which is being provided on a humanitarian basis," a ministry official said on condition of anonymity, citing official policy.
Meanwhile, Japanese Prime Minister Shinzo Abe said "we simply could not accept" a nuclear test by the North.
South Korean Vice Foreign Minister Yu Myung-hwan warned a test by the North might provoke a regional arms race and "could provide a pretext for Japan's nuclear armament."
"This will prompt countermoves by China or Russia and lead to a change in the balance of power in the Northeast Asia," Yu said.
The leaders of China, Japan and South Korea plan meetings in the coming days _ trips scheduled before North Korea announced its nuclear test intentions. Abe will head to China on Sunday and to Seoul on Monday, and Roh will travel to Beijing on Oct. 13.
Russia, another key Pyongyang ally, has urged the North to show restraint. Defense Minister Sergei Ivanov also voiced concern Wednesday about the environmental fallout from a possible nuclear test.
In Australia, North Korean Ambassador Chon Jae-hong was summoned Wednesday and "was warned in the strongest possible terms of the severe consequences should North Korea conduct a nuclear test," Foreign Minister Alexander Downer said in a statement.
Pyongyang has not conducted any known test to prove its claim that it has nuclear weapons. Some experts believe the North has enough radioactive material to build half a dozen or more nuclear bombs, though there are doubts about whether it could deliver them accurately on a warhead.
Although North Korea is dotted with underground military installations, media reports in South Korea have identified North Hamkyong province on the North's northeast coast as a likely site for a nuclear test.