According to its official statements, North Korea is ready to go to the brink. But how serious are Pyongyang's threats?

This week, new U.N. sanctions punishing the North's successful December rocket launch have elicited a furious response from Pyongyang: strong hints that a third nuclear test is coming, along with bigger and better long-range missiles; "all-out action" against its "sworn enemy," the United States; and on Friday, a threat of "strong physical countermeasures" against South Korea if Seoul participates in the sanctions.

"Sanctions mean war," said a statement carried by North Korea's official Korean Central News Agency.

In the face of international condemnation, North Korea can usually be counted on for such flights of rhetorical pique. In recent years it threatened to turn South Korea into a "sea of fire," and to wage a "sacred war" against its enemies.

If the past is any indication, its threats of war are overblown. But the chances it will conduct another nuclear test are high. And it is gaining ground in its missile program, experts say, though still a long way from seriously threatening the U.S. mainland.

"It's not the first time they've made a similar threat of war," said Ryoo Kihl-jae, a professor at the University of North Korean Studies in Seoul. "What's more serious than the probability of an attack on South Korea is that of a nuclear test. I see very slim chances of North Korea following through with its threat of war."

Although North Korea's leadership is undeniably concerned that it might be attacked or bullied by outside powers, the tough talk is mainly an attempt to bolster its bargaining position in diplomatic negotiations.

The impoverished North is in need of international aid and is eager to sign a treaty bringing a formal end to the Korean War, which ended nearly 60 years ago in a truce. It uses its weapons program as a wedge in the ever-repeating diplomatic dance with the U.S.-led international community, and there is no reason to believe this time is different.