Obama calls North Korea a 'massive challenge'

President Obama said that he's ordered the military to further protect the interests of the U.S. and its allies in Asia amid North Korea's aggressive military moves.

"One of the things that we have been doing is spending a lot more time positioning our missile defense systems, so that even as we try to resolve the underlying problem of nuclear development inside of North Korea, we're also setting up a shield that can at least block the relatively low-level threats that they're posing right now," Obamatold CBS in an interview aired Tuesday morning in response to Pyongyang's submarine-launched ballistic missile test over the weekend.

On Thursday, responding to North Korea's unsuccessful ballistic missile test that was aimed at demonstrating that Pyongyang can reach U.S. facilities in the region, White House spokesman Josh Earnest explained that the Pentagon determined that previous movement of military defenses to the region in response to previous failed tests sufficiently protect the U.S. and regional allies.

"[U]nfortunately, I've had the occasion to discuss several times over the course of the last three or four months the steps that the United States has taken to bolster our missile defense capabilities in the region," Earnest said. "And these are missile-defense capabilities that have been shifted to this region of the world in response to this threat. And this includes the deployment of some naval assets to the region, as well as the deployment of some assets to Alaska to ensure that the U.S. homeland remains safe," he said.

Obama called North Korea's "erratic" behavior "a massive challenge." He also said that dictator Kim Jong-un is "irresponsible enough that we don't want them getting close" to U.S. allies such as South Korea and Japan.