South Korea said yesterday that news of preliminary US findings of radioactivity near North Korea only confirmed its assumption that the communist regime had tested an atom bomb as claimed.
"The government has been mapping out measures on the assumption that the announced nuclear test was genuine," said Yoon Tae-young, a spokesman for President Roh Moo-hyun.
"Therefore, there is no change in the way the government is handling the situation just because radioactivity was detected," he told the national news agency Yonhap.
Last Monday, North Korea sparked worldwide condemnation with its announcement it had carried out its first atom bomb test, heightening tensions on the Korean Peninsula, which has been divided since the 1950-53 Korean War.
Seismic readings in South Korea and elsewhere confirmed an earthquake-strength blast had taken place, but by Friday there had not been independent verification it was a nuclear device.
However, a US official later told reporters that "there is preliminary data analysis that suggests that the event in North Korea was consistent with a nuclear explosion."
The official, who spoke on condition of anonymity, said that US intelligence was doing additional tests of collected samples to make a final determination, expected within days.
CNN and news agencies in South Korea and Japan earlier reported that US officials had informed Seoul and Tokyo they had detected radioactive particles, suggesting the underground nuclear explosion had taken place.
"This morning we were informed by the US side that radioactivity was detected after analyzing the air near the site of the nuclear test," Yonhap quoted a South Korean intelligence source as saying.
A South Korean intelligence source confirmed the information had been passed along to Seoul from the United States.
The news about the preliminary US test results, all quoting unnamed US government officials, came hours after UN discussions on how North Korea should be punished for the tests.
Last-minute Chinese and Russian objections to a compromise draft resolution on mandatory sanctions against North Korea cast doubt on prospects for a vote yesterday, diplomats said.
If confirmed, the radioactivity finding would reverse earlier media reports that suggested air samples collected by a US military aircraft on the day after the Oct. 9 explosion showed "no evidence of nuclear debris."
Japan also said on Tuesday no unusual radiation levels had been detected in dust samples collected by its military planes.
South Korea said Saturday it had still measured no fallout from the test so far on its own territory.