Fox is reporting, but neither South Koreans nor U.S. intel is confirming.
South Korean officials couldn't immediately confirm the report.
South Korean President Roh Moo-hyun has convened a meeting of security advisers over the issue, Yonhap reported, and intelligence over the test has been exchanged between concerned countries.
AP copy should be updating, here.
Successful? (AP update)
The country's official Korean Central News Agency said the test was performed successfully and there was no radioactive leakage from the site.
"The nuclear test is a historic event that brought happiness to the our military and people," KCNA said.
On like Donkey Kong? Or, is the "official" News Agency just bringing us that special brand of state-controlled news that's, you know, not true? You know, like Kim Jong's golf scorecard? (Yes, I'm being a little flippant. I laugh that I may not weep.)
Update: A South Korean news agency has a time on the test.
South Korea's Yonhap news agency said the test was conducted at 10:36 a.m. (9:36 p.m. EDT Sunday) in Hwaderi near Kilju city, citing defense officials.
Update: Did you feel that? U.S. Geological Survey reports no seismic activity in N. Korea, according to Fox.
Update: More on that tremor, from tdau1997 in comments.
South Korea announced it detected a 3.58-magnitude seismic tremor at about 11:30 AEST.
"The government has received a report that there was a tremor of 3.58 sensed from North Korea's northern Hamkyong province at 10:36am (11:30 AEST)," said foreign ministry spokesman Choo Kyu.
Fox is confirming the U.S. Geological Survey finding of no seismic activity, however.
Update: Stop the ACLU is also following.
Update: Fox again-- the U.S. Geological Survey reports that there is some seismic activity coming in now, but no location or magnitude. A team of geologists will have a statement in half an hour.
Update: U.S. Official: China got a 20-minute warning, immediately informed S. Korea, U.S., and Japan, according to Fox again.
Update: Japan speaks, coming over the AP wire:
Japanese Prime Minister Shinzo Abe says information still needs to analyzed to determine whether North Korea truly conducted nuclear test.
Japan's security council will be meeting shortly.
Update: S. Korean Defense Ministry raises alert level.
Update: AP alert on the tremors reported by S. Korea (emphasis mine):
South Korean seismic monitoring center confirms tremors felt at time of alleged North Korea nuclear test were not natural occurrence.
Update: Senior Bush administration official says something did happen, and they're almost positive it was a nuclear test. The U.S. received early warning from the Chinese.
Update: AP update on the tremor discrepancy between S. Korea and the U.S. Geological Survey.
The U.S. Geological Survey said it had detected no seismic activity in North Korea, although it was not clear whether a blast would be strong enough for its sensors.
Fyi, the USGS picked up readings on an earthquake near Tonga, in the South Pacific today, just to get an idea of range.
Update: If this ends up being true, it will serve to make this TIME magazine cover look rather silly. It was already more than a bit melodramatic, and this makes the melodrama and thinly veiled excitement by the graphics artist look even tackier.
And, the Dems who rejoice over the cover despite the change in the news cycle will bypass tacky and go straight to stupid. Oh, look, there they go now!
Update: Mark it down. 12:26 a.m., an hour and a half into a likely international crisis, DU questions the timing in a thread named, I kid you not, "October Surprise. How Convenient." Priorities.
Update: Bob Owens IMs with this, which he's now posted:
I suspect that we'll find out that this was a real test of a small nuclear warhead, but I would not be surprised in the least to find out that this was a large conventional blast like we had planned earlier this year in Nevada in an operation named "Divine Strake."
Update: USGS now reports 4.2 magnitude tremor in N. Korea.
At Op-For, John has ominous words:
Back then it was just one errant missile. Today we're talking about a nuclear weapon. A nation killer. A world killer. And it's in the hands of a man whose sanity is suspect and is worshipped as a god by an army of over one million.
Korea is simply too small of a theater to be playing with nuclear toys. You can bet your britches that the far east paradigm just shifted, big time. Let the arms race begin...
Update: China speaks. From an AP alert:
China says Beijing "resolutely opposes" the North Korean nuclear test and hopes Pyongyang will return to disarmament talks.
Update: James Rosen of Fox reports on what the U.S. will look for from the UN Security Council.
A very strong Chapter 7 resolution to make it illegal to transfer missile technology of any kind to N. Korea and make it harder to trade with the rogue nation. Will not seek an energy cut-off from China, as China doesn't want the resulting refugees on its doorstep.
There's a Presidential statement due tonight some time, and another one expected tomorrow.
Update: WH spokesperson issues statement, confirms that the WH has been getting the same reports we've been getting, calls the test a "provocative act," and "defiance of the will of the international community." Looking for a link.
Bush administration on the phone tonight with China and S. Korea.
Update: Bryan analyzes the likely diplomatic and military, err, fall-out from this test. Read the whole thing.
I'm having trouble staying awake (kinda wimpy, I know), so if I trail off in mid-sentence or something, you'll know what the deal is.
Update: Was Kim Jong Il's big explosion an anti-climax? American intel officials are saying it was "more fizz than pop," according to Fox. According to an AP alert, "South Korean expert says North Korea's test was relatively small, equivalent to 550 tons of TNT."
Hmm, paging Bob Owens.
Allah makes this point:
Update: I saw this report a few minutes ago at FR but dismissed it. Now Fox has a teaser up about it. Could the yield really have been only 550 tons of TNT? That’s half a kiloton. Compare and contrast:
The Boeing 767 and Boeing 757 that slammed into the WTC were carrying a combined total of about 200,000 pounds of jet fuel, and the combined power of the explosions was about 1,000 tons of TNT, a kiloton.
550 tons is an awfully small explosion, relatively speaking. Are we sure this was nuclear?
Update: Meanwhile, John Kerry is taking a very serious, tough stance on the pressing, major issues of October 2004. Can I get an 'Amen' for this guy not being President?
Update: AP rounds up possible next steps.
All right, I'm gonna head to bed for now. Allah's the nightowl, so check in with him if you're jonesing. I'll be back soon.