All Eyes On North Korea

Gunfire rang out Saturday along the heavily armed no man's land separating the divided Koreas, as regional tensions mounted in anticipation of communist North Korea's plan to test its first atomic bomb.

South Korean soldiers fired about 40 shots as a warning after five North Korean soldiers crossed a boundary in the Demilitarized Zone separating the two country's forces, South Korean military officials said.

It was unclear whether the North Korean advance, which occurred shortly before noon near a stream, was intended as a provocation, an official at South Korea's Joint Chiefs of Staff said on condition of anonymity, citing official policy. No one was hurt, and the North Koreans retreated.

"It's not clear whether it was intentional or whether it was to catch fish," he said, adding that four of the North Koreans were unarmed, and the fifth carried a rifle.

Earlier in the day, North Korea's neighbors applauded a U.N. Security Council statement warning the country not to follow through on its threats to test its first nuclear weapon, perhaps as early as Sunday. Japan said it will push for punitive measures if Pyongyang doesn't heed international opinion.

The statement adopted by the council on Friday also called on North Korea to return immediately to talks on scrapping its nuclear weapons program or face unspecified consequences.

"North Korea's declaration that it would conduct a nuclear test threw down the gauntlet, forcing the U.N. Security Council to act," said CBS News foreign affairs analyst Pamela Falk, "but the proposed resolution does not go very far to lay out the consequences if the test occurs."

South Korea's Foreign Ministry issued a statement Saturday saying it supported the appeal and also urging its isolated, communist neighbor to resume the long-stalled six-nation talks.

"North Korea must clearly recognize that a nuclear test would not help the North itself in any way," South Korea said. "North Korea should be held responsible for any consequences that could be caused by a test."

Stepping up shuttle diplomacy, South Korea's nuclear envoy said he will visit Beijing on Monday for two days of talks with Chinese officials about the nuclear test.

Separately, Japan's Foreign Ministry said it sees a nuclear test by North Korea as "a grave threat to the peace and security of northeast Asia and the world" and welcomed the Security Council statement.

"If North Korea conducts a nuclear weapons test despite the concerns expressed by international society, the Security Council must adopt a resolution outlining severely punitive measures," the ministry said in a statement.

The statement adopted unanimously on Friday expresses "deep concern" over North Korea's announcement Tuesday that it planned a test, a move that would confirm strong suspicions it is a nuclear power.

The warning was read at a formal meeting by the council president, Ambassador Kenzo Oshima of Japan, who indicated that the North could face sanctions or possible military action if it detonates a nuclear device.

The council acted amid speculation that a nuclear test could come on Sunday, the anniversary of North Korean leader Kim Jong Il's appointment as head of the Korean Workers' Party in 1997. Japanese Vice Foreign Minister Shotaro Yachi, currently in Washington, told Japan's TV Asahi, "Based on the development so far, it would be best to view that a test is possible this weekend."

With tensions rising, Kim met hundreds of top North Korean top military commanders and urged them to bolster the nation's defenses, as officers cheered, "Fight at the cost of our lives!" the North's official Korean Central News Agency reported Friday.

A North Korea expert in China, the North's closest ally, said only the removal of American economic sanctions against Pyongyang could dissuade the country from carrying out a nuclear test.

"North Korea has already made a decision to carry out a test," said Li Dunqiu, of China's State Council Development Research Center, a Cabinet-level think tank. But "if the U.S. removes sanctions ... then tensions can be eased. Otherwise launching a nuclear test is unavoidable for North Korea."

The United States imposed economic restrictions on North Korea last year to punish it for alleged counterfeiting and money laundering. Since late last year, North Korea has boycotted six-nation talks aimed at dismantling its nuclear ambitions.

"North Korea's deputy foreign minister was clear in last month's General Assembly session that Pyongyang wants financial sanctions lifted," Falk added, "but the threat is real and makes it more difficult for the nations involved in the six-party talks to offer North Korea incentives."

North Korea said Tuesday it decided to act in the face of what it claimed was "the U.S. extreme threat of a nuclear war," but gave no date for the test. Washington has repeatedly said it has no intention of invading North Korea.

Both China and Russia have urged the United States and North Korea to hold talks.

But Russia's U.N. Ambassador Vitaly Churkin said U.S. Ambassador John Bolton told the council that there would be no North Korean-U.S. talks except in the margins of resumed six-party talks.

Bolton said the Security Council needs to adopt a long-term strategy to deal with North Korea but the top U.S. priority now is to stop a nuclear test.

Oshima, the Japanese U.N. ambassador, had pressed to have the statement adopted before Japanese Prime Minister Shinzo Abe travels to China on Sunday and South Korea on Monday with a message that the North should stop testing.