Almost 24 hours after North Korea’s latest nuclear test, there is still squabbling and debate over exactly what transpired.  Pyongyang insists it detonated a hydrogen bomb in an underground cavern at the Punggye-ri Test Facility, in the northeastern corner of the DPRK, not far from the Sea of Japan.  But experts in the U.S. and other western countries expressed doubt, saying the explosion detected wasn’t powerful enough to be an H-bomb.

Of course, the back-and-forth is (at this point) little more than a semantics-and-science debate.  Even if Kim Jong-un’s regime didn’t test a fusion weapon, they did manage to thumb their nose at the world community by conducting yet another nuclear test, with a weapon that is more advanced than previous models.

And there were clear indications that something was about to happen, at least from a rhetorical perspective.  Last month, Kim claimed that North Korea had become a “powerful nuclear weapons state,” ready to detonate a “self-reliant A-bomb and H-bomb.”  That remark brought a few chuckles among arms experts; Pyongyang’s three previous nuclear tests, in 2006, 2009 and 2013, had been low-yield affairs, demonstrating only a fraction of the power of the U.S. bomb that leveled Hiroshima in 1945.  That particular weapon had a yield of 12-15 kilotons.  By comparison, the estimated yield of North Korea’s first nuclear test was roughly .5 KT; their 2009 blast had a force of 6 KT, while the 2013 and 2015 weapons had a projected yield of 4 KT.

Had Pyongyang actually tested a true fission weapon, the blast would have been much larger.  For example, the warheads on a Minuteman III ICBM deliver a yield of at least 330 KT; the larger weapons on a Trident D-5 SLBM have an explosive force equivalent to one million tons of TNT (1 megaton).  But even that pales in comparison to one of the largest nuclear weapons in the U.S. arsenal, the warhead mounted on the long-retired Titan II ICBM.  That particular weapon had a yield of 10 MT.  Russia, which had accuracy problems with its early delivery platforms, had fusion weapons that were even larger.

Some analysts believe yesterday’s test in North Korea may have involved a “boosted” weapon–a design that utilizes a brief fusion reaction to increase the power of a fission-based weapon.  If that scenario is confirmed, it would indicate that Pyongyang has the ability to produce more sophisticated bombs, and is on the path to producing a true H-bomb, which would be far more powerful than anything currently in the DPRK arsenal.

But even a “boosted” device gives reason for pause.  In a commentary for CNN last month, Bruce Bennett of RAND noted that a boosted weapon with a 50KT yield could kill as many as 250,000 people, if detonated over a densely-populated urban area like Seoul.  That potential death toll is roughly equal to 2.5% of the city ‘s population, and Pyongyang would likely use “several” nuclear weapons against the South Korean capital.

As scientists try to discern the type of weapon detonated in the most recent DPRK test, there are whispers that our intelligence community was scrambling to collect against the event.  CBS’s David Martin, reporting from the Pentagon, said defense officials believed a North Korean test would happen in the near future, but “had no clue” it would happen today.

Sputnik News, citing Japanese press reports, claims a USAF RC-135V “Rivet Joint” reconnaissance aircraft launched from Kadena AB, Okinawa around 10:30 am this morning (local time), just minutes before North Korea conducted its latest nuclear test.But Rivet Joint is an odd choice to monitor a nuclear detonation.  If the US intelligence community believes such a test is imminent, the Air Force normally deploys a WC-135 Constant Phoenix aircraft, which has the ability to collect and analyze nuclear material that enters the atmosphere, even after an underground blast.

For a Korea mission, Constant Phoenix also operates from Kadena.  So far, there has been no report of that aircraft staging from the base on Okinawa, or any other U.S. airbase in the Far East.The RC-135V, which routinely operates from Kadena, is a SIGINT platform and would be very helpful in collecting ELINT and communications data associated with the test.  However, it lacks the ability to collect nuclear signatures which would be essential in determining the type of weapon detonated and its yield.

Additionally, if the Rivet Joint’s mission was to monitor DPRK emitters and comms during the test window, it would have probably launched earlier, not 10 minutes before the blast.  The take-off time for the RC-135 was probably unrelated to the nuclear test, another indication we were surprised by the blast.

Thursday afternoon, a Pentagon official told NBC News that a “drone” was used to collect nuclear material over the Sea of Japan following the test.  That is likely a reference to a pair of USAF Global Hawk UAVs, which have been deployed to Misawa AB, Japan since May of 2014.  When the deployment was announced, American officials listed nuclear monitoring as one of their primary missions.  That detachment concluded its operations and redeployed to the U.S. in the fall of 2014.

According to an Air Force media release, the Global Hawks returned to Misawa in May of last year, starting a deployment that was supposed to last through December.  US officials have not said how long the high-altitude UAV was on station at the time of the test, although the RQ-4 can remain aloft for days at a time.

The run-up to the latest NK nuclear test was also interesting from another perspective.  In the past, intelligence sources have often leaked word of detected preparations, to let Pyongyang know that the U.S. is aware of its activities.  This time, there were no stories in The New York Times or Washington Post about a pending test, suggesting that American officials decided to remain quiet, or they weren’t convinced that Kim Jong un would soon detonate another nuke.  If that latter scenario proves true, it might indicate that North Korea has developed improved denial and deception  (D&D) techniques that help mask test preparations.  The DPRK retains one of the most extensive–and sophisticated–deception programs in the world.

In response, the U.S., Japan, South Korea and China have all condemned the test.  But such protests carry little weight in North Korea.  Once again, Kim Jong un has succeeded in shifting the world’s attention to the hermit kingdom, a sure indicator that he wants something–perhaps a better nuclear “deal” like the once recently concluded between Washington and Iran.

As with recent developments in the Persian Gulf, the latest provocation from Pyongyang raises the specter of another, regional nuclear arms race.  With U.S. power receding on the world stage, there is quiet talk in Seoul, Tokyo and even Taipei about acquiring an “independent” nuclear force to deter North Korea’s small, but growing, arsenal.   Given the industrial, technological and financial resources possessed by those three nations, a nuclear arms race in northeast Asia could unfold extraordinarily fast, and with grave ramifications for all concerned.