The U.S. is putting a pause to what several officials described as a step-by-step plan the Obama administration approved earlier this year, dubbed “the playbook,” that laid out the sequence and publicity plans for U.S. shows of force during annual war games with South Korea. The playbook included well-publicized flights in recent weeks near North Korea by nuclear-capable B-52 and stealth B-2 bombers, as well as advanced F-22 warplanes.

The U.S. stepped back from the plans this week, as U.S. officials began to worry that the North, which has a small nuclear arsenal and an unpredictable new leader, may be more provoked than the U.S. had intended, the officials said.

“The concern was that we were heightening the prospect of misperceptions on the part of the North Koreans, and that that could lead to miscalculations,” a senior administration official said.

Officials said the U.S. didn’t believe North Korea had any imminent plans to take military action in response to the exercises. Rather, the shift reflects concerns within the administration that the North, caught off guard, could do something rash, contrary to intelligence assessments showing that it is unlikely to respond militarily to the U.S. show of force.