A top U.S. military commander on Sunday accused the Democratic People's Republic of Korea (DPRK) of continuing to destabilize the region after the country showed an American nuclear scientist last week a vast new facility designed to enrich uranium.

"From my perspective, it's North Korea (DPRK) continuing on a path which is destabilizing for the region," Admiral Mike Mullen, chairman of the U.S. military's Joint Chiefs of Staff, told CNN's "State of the Union" program.

"It confirms or validates the concern we've had for years about their enriching uranium -- which they deny routinely," said Mullen.

DPRK showed Siegfried Hecker, a nuclear scientist from Stanford University, a plant where he saw "hundreds and hundreds" of centrifuges, the New York Times said on Sunday. Siegfried said the DPRK claimed 2,000 centrifuges were already installed and running, and he was "stunned" by the sophistication of the new plant, according to the report.

"All of this is consistent with belligerent behavior, the kind of instability-creation in a part of the world that is very dangerous," Mullen said.