The report by a United Nations watchdog on Friday that North Korea had made "significant progress" on a new nuclear reactor apparently delighted North Korea, which boasted it would expand its nuclear capabilities "far beyond US imagination."

The North didn't specifically confirm the International Atomic Energy Agency's report detailed by Reuters' Fredrik Dahl, based on satellite images, that it was developing an experimental light water reactor, but it sure didn't deny it. Rather, in typically vague saber-rattling form, the North Korean foreign ministry issued a memorandum that "said the North had no choice but to prolong the possession of nuclear weapons 'unless the United States makes a right choice,' " according to Channel News Asia. "Our nuclear deterrent will be modernised and expanded far beyond US imagination," the North said. Keeping in mind that North Korea's military threats don't always go as planned (remember the fake missiles and the botched rocket launch?), it would appear this time the IAEA is at least giving the North something solid on which to base its threats, without having to tip its own hand, as it reports progress on this new reactor. Per Reuters' Dahl:

The IAEA said "significant progress" had been made in the reactor's construction since its previous report a year ago.

That included a dome that had been put in place on the reactor containment building and indications that some components may have been installed inside the building.

A system for pumping water from a river to the reactor for cooling purposes has also been built, the IAEA report said.

"However, without access to the site, the agency is unable to assess either the design features of the LWR or the likely date for its completion," the Vienna-based agency said.

The North has been touting its readiness for another nuclear test for some time, and still hasn't done it, but the latest from IAEA suggests there's evidence it is making progress.