SEOUL, South Korea — In her harshest criticism yet of North Korea, the incoming president of South Korea, Park Geun-hye, warned on Wednesday that the North’s pursuit of nuclear weapons would bring its government “self-destruction.”

Ms. Park’s comment came a day after North Korea defied worldwide warnings Tuesday by detonating what it called a miniaturized atomic bomb in its third nuclear test.

It remained unclear how close North Korea has come to building a nuclear warhead small enough to fit onto intercontinental ballistic missiles — seen as the ultimate goal of the North’s nuclear and missile programs. But the latest detonation was more than a nuclear test; it also tested the abilities of the new governments in the region to tame the North’s nuclear and missile ambitions.

The test led to a new chorus of international outrage and threats of more sanctions, even though such responses have had little to no effect on North Korea’s behavior after its previous tests.