South Korean analysts said Mr. Kim seemed to have decided instead to celebrate his grandfather’s birthday not with a nuclear test or a launch, but with a military parade meant to demonstrate his missile capabilities to his American foes.
To military analysts scrutinizing North Korea’s broadcast of the parade, the most noteworthy element seemed to be three types of long-range ballistic missile, one of them apparently new.
While the North has repeatedly claimed that it can strike the United States with a nuclear warhead, it has never flight-tested an intercontinental ballistic missile capable of crossing the Pacific.
In addition, some analysts doubt that the country has mastered the skills to build a warhead that can survive re-entry from space, or one small enough to mount on a long-range missile. They said the intercontinental ballistic missiles, or ICBMs, that have been displayed in recent North Korean military parades might have been mock-ups of systems still under development.
In a New Year’s Day speech, however, Kim Jong-un claimed that his country was in the “final stage” of preparations for its first ICBM test.
One missile showed off on Saturday was the KN-08, which the North first displayed in a 2012 parade and is widely believed to have been its first attempt at an intercontinental ballistic missile.
Behind the KN-08 were launching tubes that analysts said appeared to have been designed for two other kinds of long-range ballistic missiles. There were multiple examples of each tube; it was impossible to see what was in them, but analysts said it was likely that they contained missiles that were either completed or under development.
Kim Dong-yub, a missile expert at the Institute for Far Eastern Studies at Kyungnam University in Seoul, said one kind of tube appeared to be for the KN-14, a modified version of the KN-08 that was first displayed in a parade in 2015, during which the North claimed that its missiles were tipped with nuclear warheads.
The other tube design was new to the analysts. ”Given the size, it looks like it contains a new ballistic missile with a range of 6,000 kilometers,” or 3,700 miles, said Shin In-kyun, a military expert who runs Korea Defense Network, a civic group specializing in military affairs. “Officials in the region will scramble to figure out whether this is a new solid-fuel, long-range ballistic missile the North was believed to be developing.”
Almost all of the North’s other ballistic missiles use liquid fuel, which can take hours to load. Solid fuel loads quickly and is easier to transport; North Korean missiles that use it could be kept on mobile launchpads, hidden in the country’s elaborate tunnel system and launched on short notice.
The Pukguksong-2, an intermediate-range ballistic missile that the North tested in February, uses solid-fuel technology. That missile was displayed in a parade for the first time on Saturday. So were the Pukguksong-1 — Pyongyang’s first submarine-launched ballistic missile, which it successfully tested in August — and the Scud-ER, a Scud with an extended range, designed to reach American military bases in South Korea and Japan.
North Korea launched four Scud-ERs simultaneously last month, some of them splashing down in waters in Japan’s exclusive economic zone.
The North’s totalitarian regime uses military parades to show off its armed forces to its external enemies and demonstrate strength to its people, who have long suffered under international sanctions and economic mismanagement. On Saturday, neat columns of soldiers and citizens chanted slogans of loyalty to Kim Jong-un and waved pink and red artificial flowers in synchronized moves.
This year’s parade was watched especially closely in light of the unusual level of regional tension. A United States naval strike group led by the aircraft carrier Carl Vinson was sent to the area in an attempt to deter Pyongyang from testing another nuclear device or missile.
Aides to President Trump have said they were not ruling out military options in dealing with the North.
On Friday, the North Korean military threatened to launch its own pre-emptive nuclear strikes at American military bases in South Korea, Japan and beyond. Warning of “storm clouds gathering,” China, the North’s main ally, urged both sides to exercise restraint.
North Korea kept up its defiant rhetoric on Saturday. “If they attempt a full-scale war, we will respond with a full-scale war,” Choe Ryong-hae, a senior official in the ruling Workers’ Party and a key aide to Mr. Kim, said in a speech before the parade. “If they start a nuclear war, we will respond with nuclear strikes.”
One surprise from the parade was the re-emergence of Gen. Kim Won-hong, the former head of the powerful secret police, the State Security Ministry.
South Korea’s National Intelligence Service had said that General Kim was dismissed and demoted in January on charges of corruption and abuse of power. In recent months, he has been absent from state functions, including a parliamentary meeting on Tuesday, spurring speculation that he might have been purged and sent to a re-education camp.
But on Saturday, he was among the generals on the reviewing stand. His uniform bore his four-star insignia, but he appeared to have lost a considerable amount of weight.