South Korea and Japan have applauded the U.N. Security Council's expression of "deep concern" about North Korea's threat to conduct a nuclear test, and Japan called for "severely punitive measures," if a test does take place. Pyongyang has so far remained silent. Meanwhile, tensions were evident, as South Korean troops fired warning shots, after five North Korean soldiers briefly crossed into the Demilitarized Zone that divides the peninsula.
Five North Korean soldiers crossed the heavily fortified Demilitarized Zone that separates the two Koreas, and fled back only when South Korean soldiers fired warning shots at them.
The South Korean military says only one of the five North Koreans was armed, and they ignored several warnings over a loudspeaker before the shots were fired.
A South Korean military official was quoted as saying that it was unclear whether the action was an intentional provocation, or whether the men had crossed the line to go fishing.
If it was a provocation, it supported the suggestion by Peter Beck, North Asia director for the International Crisis Group, that the U.N.'s Friday statement of concern is unlikely to influence the North's behavior.
"It's a nice-sounding statement, but it's just that: a statement. It's not a resolution, there's no explicit enumeration of consequences the North will face if it does test," he said.
Pyongyang announced this week that it would conduct a nuclear test - its first - at an unspecified time in the future. The U.N. Security Council warned against such an act, but stopped short of threatening new sanctions, if Pyongyang ignores the warning.
Seoul's Foreign Ministry backed the U.N. Saturday, saying the North must realize a nuclear test "would not give it any benefits."
Japan's Foreign Ministry called on the council to take "severely punitive measures" against the North, if a test is carried out. Japan's Nihon Keizai newspaper reported Saturday that Tokyo would seek to strengthen its own unilateral sanctions against Pyongyang, if the test went forward.
Japan's new prime minister, Shinzo Abe, is scheduled to visit both China and South Korea to discuss the North Korean nuclear issue over the next two days. South Korea says it is sending an envoy to China next week for the same reason.
Both China and South Korea have been reluctant to pressure North Korea, hoping instead to influence its behavior through economic engagement. However, experts say a nuclear test will create intense pressure for them to adopt a firmer stance toward the North.
The U.N. Security Council took action against North Korea in July, when it unanimously condemned the North's test launch of at least seven missiles - again, after it was warned not to do so.
For more than a year, North Korea has boycotted talks at which South Korea, China, Japan, Russia and the United States have tried to persuade it to give up its nuclear programs, in exchange for diplomatic and economic benefits.
Pyongyang says the boycott is a response to sanctions Washington placed on North Korean financial interests. The United States says those measures are a law enforcement matter aimed at fighting alleged money-laundering and counterfeiting by the North, and are not linked to the six-party talks.