North Korea fired hundreds of artillery shells in waters near South Korean border islands on Jan. 5. Last week, it said it no longer regarded the South as inhabited by “fellow countrymen” but as a “hostile state” it would subjugate through a nuclear war. On Friday, it said it had tested an underwater nuclear drone to help repel U.S. Navy fleets.

That new drumbeat of threats, while the United States and its allies have been preoccupied with the wars in Ukraine and the Middle East, has set foreign officials and analysts wondering whether the North’s leader, Kim Jong-un, has moved beyond posturing and is planning to assert more military force.

For decades, a central part of the North Korean playbook has been to stage carefully measured and timed military provocations — some aimed at tightening internal discipline, others at demanding attention from its neighbors and the United States, or all of that at once.

But to several close watchers of North Korea, the latest round of signals from Mr. Kim feels different. Some are taking it as a clue that the North has become disillusioned with seeking diplomatic engagement with the West, and a few are raising the possibility that the country could be planning a sudden assault on South Korea.

Two veteran analysts of North Korea — the former State Department official Robert L. Carlin and the nuclear scientist Siegfried S. Hecker — sounded an alarm this past week in an article for the U.S.-based website 38 North, asserting that Mr. Kim was done with mere threats. “Kim Jong-un has made a strategic decision to go to war,” they wrote.

Analysts broadly agree that North Korea has been shifting its posture in recent years, compelled by an accumulation of both internal problems, including a moribund economy and food and oil shortages, and frustrations in its external diplomacy, like Mr. Kim’s failure to win an end to international sanctions through direct diplomacy with President Donald J. Trump. And most agree that the North’s recent closeness with Russia, including supplying artillery shells and missiles for use in Russia’s war in Ukraine, will be a game-changer in some way.

But there is still stark disagreement over where Mr. Kim’s new tack might be leading.

Many say that Mr. Kim’s ultimate goal remains not a war with South Korea, a treaty ally of the United States, but Washington’s acceptance of his country as a nuclear power by prompting arms-reduction talks.

“The North Koreans won’t start a war unless they decide to become suicidal; they know too well that they cannot win the war,” said Park Won-gon, a North Korea expert at Ewha Womans University in Seoul. “But they would love their enemies to believe that they could, because that could lead to engagement and possible concessions, like the easing of sanctions.”