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Obama calls for end to North Korea's 'belligerent approach'

Both the U.S. and Japan have defense systems ready should North Korea's missiles pose a threat. NBC's Richard Engel reports.

President Barack Obama called for an end to North Korea's "belligerent approach" Thursday, but said the United States will take all necessary steps to protect its people and meet its obligations to allies in the region — meanwhile, it was also officially revealed that the Pentagon believes the rogue nation likely has nuclear-capable missiles.

Following a meeting with United Nations Secretary General Ban Ki-moon in the Oval Office, Obama spoke about the situation in the Korean Peninsula for the first time in weeks.

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"We both agree that now's the time for North Korea to end the belligerent approach that they've been taking and to try to lower temperatures," Obama said. "Nobody wants to see conflict on the Korean Peninsula."

Obama added, "We will continue to try to work to resolve some of those issues diplomatically even as I indicated to the secretary general that the United States will take all necessary steps to protect its people and to meet our obligations under our alliances in the region."

U.S. officials tell NBC News they believe North Korea does have the capability to put a nuclear weapon on a missile and that they have missile deliverable nukes. Those missiles, however, cannot go more than 1000 miles. NBC's Richard Engel reports.

The North has been threatening the United States and its "puppet" South Korea almost daily in recent weeks. According to assessments by the U.S. and South Korea, the North has placed medium-range missiles on its east coast. U.S. officials said a missile could be fired "at any moment, any hour."

"We are no longer dealing with technicalities. We are dealing only with intentions," a U.S. official told NBC News.

A recent assessment by the Defense Intelligence Agency claims with “moderate confidence” that North Korea has learned how to miniaturize a nuclear weapon so that it can be mounted on a ballistic missile but that the weapon's “reliability will be low.”

The public revelation of previously undisclosed information came Thursday from Rep. Doug Lamborn during a budget hearing before the House Armed Service Committee.  The information came within “one paragraph” of the DIA assessment that had the incorrect security designation.

While the conclusion of the assessment has been publicly reported before, including in an April 3 report on NBC Nightly News, Lamborn's mention of it is the first time a government official has discussed it publicly.

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In response to the revelation, Pentagon Press Secretary George Little said it "would be inaccurate to suggest that the North Korean regime has fully tested, developed, or demonstrated the kinds of nuclear capabilities" Lamborn mentioned.

"While I cannot speak to all the details of a report that is classified in its entirety, it would be inaccurate to suggest that the North Korean regime has fully tested, developed, or demonstrated the kinds of nuclear capabilities referenced in the passage," Little said in a statement. "The United States continues to closely monitor the North Korean nuclear program and calls upon North Korea to honor its international obligations."

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Gen. James Clapper, director of National Intelligence, tried to distance the administration from the assessment, saying it is not accurate to suggest that the regime has "fully developed and tested" the kind of nuclear weapons mentioned by Lamborn. That, however, does not mean the assessment is inaccurate, as it did not say the weapons were fully tested.

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On Wednesday, Secretary of Defense Chuck Hagel said the United States was "fully prepared to deal with any contingency" or provocation that North Korea may take, but added that the U.S. hopes the rhetoric will be "ratcheted down."

NBC News' Andrea Mitchell and Robert Windrem contributed to this report.