Updated: Tue, 02 Apr 2013 08:39:05 GMT | By Ian Johnston and Jim Miklaszewski, NBC News

Panetta says US must be 'very firm' with N. Korea as it issues more threats

Former Defense Secretary Leon Panetta has warned that the United States should be “very concerned” by the level of “provocation and bellicosity” emanating from North Korea, as the rogue communist state announced it was going to restart all its nuclear facilities.

Panetta told CNBC in an interview that the U.S., Japan and South Korea had to be “very firm in sending them a message that we are going to do everything necessary to defend our security and defend our troops.” He said there was a danger of a "miscalculation" that escalated.

The North continued to make threats Tuesday, and said it would rebuild and restart nuclear facilities, including a reactor that can make one bomb's worth of plutonium a year.

Panetta said the amount of hostility emanating from Pyongyang was alarming.

“I think we've got to be very concerned about ... the level of provocation that North Korea is engaged in. They are in the process of testing ICBMs [Intercontinental Ballistic Missiles]. They've also been testing nuclear weapons,” he said.

“The kind of provocation and bellicosity they're showing now with their rhetoric raises a lot of concern,” he added. “It just means the United States and our allies Japan and South Korea have to be very firm in sending them a message that we are going to do everything necessary to defend our security and defend our troops.”

United Nations Secretary-General Ban Ki-moon took time out of an official visit to Andorra on Tuesday to say that the North Korean crisis had "already gone too far" and that he was "deeply troubled" by it.

"Nuclear threats are not a game," Ban said, adding that "things must begin to calm down" or they "could lead down a path that nobody should want to follow."

He closed his remarks by offering to facilitate peace talks, but how the North would react was not immediately clear. Ban was South Korea's foreign affairs minister before election to his UN post.

'Be very prepared'

Panetta noted that over the last 50 or 60 years the North had gone through cycles of “provocation” and “accommodation.”

“A lot of this is aimed more probably on the internal situation in North Korea, aimed at improving the new leader's credibility, his credentials as a leader,” he said.

“But at the same time since they have capabilities and [are] developing those capabilities, I don't think we can take anything for granted. The U.S., South Korea and our other partners in that region have to be very prepared in the event that something could happen here. I think the greater likelihood is miscalculation and if they do something that escalates quickly that's the greater danger,” he added.

A spokesman for the North's General Department of Atomic Energy said restarting its nuclear facilities was part of efforts to resolve the country's acute electricity shortage, but also for "bolstering up the nuclear armed force both in quality and quantity," the official Korean Central News Agency said, according to Reuters.

Pyongyang conducted its third nuclear test in February, prompting a new round of U.N. sanctions that have infuriated its leaders and led to a torrent of threatening rhetoric. The United States has sent nuclear-capable bombers and stealth jets to participate in annual South Korean-U.S. military drills that the allies call routine but that Pyongyang claims are invasion preparations.

KCNA kept up the rhetoric on its English-language site Tuesday, with an article headlined “Intensified Anti-U.S. Action Called For.”

It quoted the “North Side Committee for Implementing the June 15 Joint Declaration” as saying in a statement that the joint U.S. and South Korean military exercise “clearly proves that the U.S. imperialists' scenario to launch a nuclear war on the Korean Peninsula at any cost has reached an extremely reckless phase of its implementation.”

“As already clarified by the DPRK [North Korea], gone are the days when it could have verbal exchange with them,” the statement said.

“To wage a merciless, just, retaliatory war is the only way of rooting out the source of the danger of a nuclear war on this land and build a peaceful and prosperous reunified thriving nation where all Koreans live together,” it added.

Reuters and NBC News' Andrea Mitchell and John Newland contributed to this report.


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