Reports yesterday that North Korea may have conducted a second nuclear test stirred new anxieties, but Japanese officials said they probably jumped the gun.
Early yesterday, Japanese public broadcaster NHK and Nippon Television, a commercial network, reported that "tremors" had been detected that morning in North Korea, leading the government to begin investigating whether a second blast had taken place. The reports cited unidentified government sources.
Officials later said that it was most likely a false alarm and one of the networks issued a retraction.
North Korea on Monday announced that it had tested its first nuclear bomb, drawing global condemnation. But while experts have rushed to confirm the details of the first test, many fear the North is preparing to conduct another.
Those fears were reflected in yesterday's reports.
Nippon Television and NHK both reported that tremors had been detected early yesterday suggesting a second nuclear test, prompting a flurry of media attention and sending officials scrambling for confirmation.
But South Korean and US seismic monitoring stations said shortly afterward that they hadn't detected any activity that could indicate a possible second North Korea nuclear test. Japanese Prime Minister Shinzo Abe, speaking later to a parliamentary Upper House budget meeting, also said he had not seen any data that would confirm a second test.
"I have not received information about any indications ... that a test has taken place," Abe said.
Other officials echoed those denials.
In Washington, a senior State Department official said it wouldn't be a surprise if there were multiple tests, but so far there was no sign of any. The official spoke anonymously because of the sensitivity of the situation.
White House spokesman Blair Jones, likewise, said the US had detected no evidence of additional North Korean testing. Jones added Japanese officials thought the reported event may have been related to an earthquake that occurred in northern Japan at 8:58am.
Nippon Television later issued an apology.
"While the Japanese government is continuing to verify its information, the Meteorological Agency has not observed any seismic wave. At this point, we have not yet confirmed that North Korea has carried out a second nuclear test. While we will continue to gather information, we would like to make a correction and offer our apology," it said.
An official with NHK's public relations department who refused to be named said the company does not comment on individual reports.
But the US Geological Survey in Golden, Colorado, said NHK had contacted its offices to check on seismic activity in the region about an hour before the Fukushima earthquake.
Japanese Meteorological Agency official Yukuhiro Watanabe said that the agency had also already begun its review of data on possible tremors in North Korea before the magnitude 6 quake occurred in Fukushima, northeast of Tokyo. Watanabe also said that a review of seismic wave data had so far not shown that any unusual events had taken place in North Korea between 5am to 8:30am yestersday.