Is North Korea on the verge of another nuclear test, or not?

What’s going on at North Korea’s nuclear test site? The question arises because there’s been some confusion in reports Monday from the Korean Peninsula as to whether Pyongyang is on the verge of a fourth nuclear explosion.

It started during a Monday South Korean parliamentary session when a lawmaker asked Unification Minister Ryoo Kihl-jae whether intelligence officials have noted more personnel and vehicle traffic at North Korea’s Punggye-ri Nuclear Test Facility.

“There is such an indication,” Mr. Ryoo said, according to an Associated Press account.

This led some Seoul-based journalists to write that another nuclear test might be imminent. Bloomberg News reported, for instance, that the detonation of a North Korean nuclear device and a missile test could occur as early as this week.

But Ryoo later said he was “startled” by the way his remarks had been interpreted, and other South Korean officials moved quickly to tamp down the test speculation. A Defense Ministry spokesman said that the North does not appear to be preparing for a detonation in the near future.

“We found there had been no unusual movements that indicated it wanted to carry out a nuclear test,” the ministry spokesperson said.

Timing is the issue under discussion here. The possibility of a fourth test at Punggye-ri has been open for some time.

North Korea prepared two tunnels for nuclear tests prior to its latest such detonation on Feb. 12, US-based experts say. But only one was used. And in the days following the February test, satellite imagery showed unusually heavy foot and vehicle traffic at the test facility, where North Korea also conducted its 2006 and 2009 explosions.

“It remains unclear whether renewed activity at the site is normal for the days after a nuclear detonation or if it is an indication of Pyongyang’s intention to conduct another test in the near future. It is also unclear whether Pyongyang will be in a position to conduct another nuclear test in the near future,” wrote nuclear experts Jack Liu and Nick Hansen in late February on 38 North, a blog about North Korea produced by Johns Hopkins University.

However, given that North Korea appears intent on developing a small nuclear warhead that can fit on the top of an intercontinental ballistic missile (ICBM), another test may be only a matter of time.

The “sheer duration” of North Korea’s nuclear weapons programs means that by now, it probably has perfected a nuclear device that's miniature enough to be carried by its short-range Nodong missile, according to an analysis by David Albright, president of the Institute for Science and International Security.

It’s important to note that not all US experts necessarily agree with this conclusion. But following the Feb. 12 test, North Korea announced it had detonated a “miniaturized and lighter nuclear device with greater explosive force than previously.” So it’s certainly possible that Pyongyang has taken a big step down the road to more easily deliverable nuclear weapons.

Where will that road end?

“North Korea probably cannot deploy a warhead on an ICBM. However, with additional effort and time, North Korea will likely succeed in developing such a warhead too,” Mr. Albright writes. “More broadly, additional underground nuclear tests are bound to help North Korea produce a more sophisticated nuclear weapons arsenal that is both more deliverable and more deadly.”