U.S. Defense Secretary Leon Panetta told reporters North Korea has a clear choice between its current course of provocation and negotiating responsibly with other nations, along with providing for its people.
He was responding to the North saying it would target its "sworn enemy" the United States with rocket launches and a "higher-level" nuclear test because of the latest U.N. Security Council's resolution condemning its Dec. 12 long-range rocket launch and expanding existing sanctions against it.
White House press secretary Jay Carney had earlier said the North's comments were "needlessly provocative."
Panetta in his comments said the U.S. "is fully prepared, we remain prepared, to deal with any kind of provocation from the North Koreans," while adding that he hoped North Korea would "determine that it is better to make the choice to become part of the international family," the Defense Department said on its web site.
Panetta said while he follows intelligence on North Korea closely, it is difficult to predict whether a North Korean launch or test is imminent, based on what he's seen.
"We've seen no outward indications, but that doesn't tell you much," he said. "They have the capability, frankly, to conduct these tests in a way that [makes] it very difficult to determine whether or not they're doing it."
The United States also issued sanctions against more North Korean bank officials and businesses dealing with the North's nuclear weapons program.
Daniel Pinkston, senior analyst for the International Crisis Group covering Northeast Asia, told CNN the North's reaction to the U.N. resolution was an expected outcome. "I think they are completely outraged and insulted by it," he said.
Commenting on the threats against the United States, Pinkston told CNN: "I don't believe they have the capability, the intention or the will to invade or destroy the United States. They wish to deter interference from the U.S. or any outside powers."
Other analysts told CNN the North needs to do lot more work to master the technology needed to mount a nuclear warhead on a missile or accurately target it.
The North has conducted two nuclear tests in the past in 2006 and 2009 and some South Korean officials have said a third one might be in the cards.