‘‘I think we still have to assess just exactly what happened here,’’ Panetta told CNN in an interview Wednesday. He said part of the assessment would examine the final stage that launched the satellite ‘‘to determine, really, whether or not that did work effectively or whether it tumbled into space. I mean, that’s the issue that we need to assess.’’

Despite its technological advances and military bluster, it’s doubtful that the North intends to strike first against the U.S.

Even so, Panetta said the U.S. has the capability to prevent such a strike.

‘‘I'm very confident that American defense capabilities are able, no problem, to block a rocket like this one,’’ he told CNN when asked about the capability of U.S. missile defense systems.

North Korea has spent decades threatening but avoiding a direct confrontation with the tens of thousands of American forces in South Korea and Japan. The government has remained firmly in power despite a drought-plagued agricultural sector that leaves many North Koreans in search of food and a crumbling economy that affords few any chance of social betterment.

‘‘It is regrettable that the leadership in Pyongyang chose to take this course in flagrant violation of its international obligations,’’ White House press secretary Jay Carney told reporters. He said the U.S. would try to further isolate North Korea in response.

State Department spokeswoman Victoria Nuland called the launch ‘‘highly provocative and a threat to regional security.’’ It will only further impoverish North Koreans, she said.