SEOUL, South Korea — North Korea said on Sunday that the two projectiles it fired a day earlier were a new type of missile, making this the third new short-range ballistic missile or rocket system the North has successfully tested in less than a month as Washington struggles to resume talks on denuclearization.
The two missiles were launched off North Korea’s east coast on Saturday in its second weapons test in the past week. On Sunday, North Korea’s official Korean Central News Agency released photographs of Kim Jong-un, the North Korean leader, watching what it called the launching of “another new weapon system.”
After scrutinizing the photos, outside analysts said the missiles, fired from a tracked mobile launcher with two missile tubes, were of a type unveiled for the first time.
North Korea has conducted five weapons tests since July 25, all of them in violation of United Nations resolutions, according to South Korea. They include a new short-range ballistic missile, known as KN-23 among outside analysts, which they said resembled Russia’s Iskander missile in its flight pattern and other traits. The North also tested a new multiple-tube rocket launcher.
The test on Saturday “looks like a new short-range ballistic missile,” likely with a purpose similar to that of the KN-23, said Michael Duitsman, a research associate at the Middlebury Institute of International Studies in Monterey, Calif. “I am not sure why North Korea would need two different missiles for the same role.”
But the unveiling and testing of a new missile leaves little doubt that despite President Trump’s insistence that his on-again, off-again diplomacy with Mr. Kim is making progress toward denuclearization, North Korea has continued to modernize and expand its missile capabilities.
“North Korea had not one but two short range ballistic missile under development this year,” Melissa Hanham, a missile expert at One Earth Future Foundation, said on Twitter. “This is not denuclearizing, this is not even close.”
Mr. Trump has shrugged off North Korea’s recent weapons tests, calling them “smaller ones” that involved neither nuclear explosions nor intercontinental ballistic missiles. But the North’s short-range missiles present a potent threat to South Korea and Japan, both key allies of the United States, as well as to the American troops and civilians in both countries.
The president’s attitude has essentially given North Korea a free hand in developing and testing its short-range weapons, analysts said. On Saturday, Mr. Trump said that Mr. Kim had sent him a letter with a “small apology” explaining that North Korea was conducting tests to counter an American military exercise with South Korea that Mr. Trump has himself criticized as too expensive.
On Sunday, North Korea invoked Mr. Trump’s comments to argue that the South had no business complaining about its recent weapons tests.
“With regard to our test for developing the conventional weapons, even the U.S. president made a remark which in effect recognizes the self-defensive rights of a sovereign state, saying that it is a small missile test which a lot of countries do,” Kwon Jong-gun, a North Korean Foreign Ministry official, said in a statement carried Sunday by the North Korean news agency.
All three of the new missile and rocket systems tested by the North in recent weeks are significant advances for the North Korean military, analysts said.
They all used solid fuel and were fired from mobile launchers. Such missiles and rockets are easier to transport and hide, especially in a mountainous country like North Korea, and take less time to prepare for launching than the North’s old missiles that used liquid fuel, they said.
The weapons also appeared to be maneuvered during flight, making it more difficult for South Korean and United States missile defense systems to intercept them, the analysts said.
“North Korea is modernizing its weapons to replace old ones,” said Kim Dong-yub, a military expert at the Institute for Far Eastern Studies in Seoul, the South Korean capital. “They flew a bit longer, at lower altitudes and faster.”
The North’s recent weapons tests also highlight how quickly inter-Korean relations have deteriorated despite the three summit meetings last year between Mr. Kim and President Moon Jae-in of South Korea.
All the missiles and rockets were launched early in the morning, breaking a promise Mr. Kim made to Mr. Moon during their first meeting in April last year.
“I heard you had your early-morning sleep disturbed many times because you had to attend the National Security Council meetings because of us,” Mr. Kim told Mr. Moon. “Getting up early in the morning must have become a habit for you. I will make sure that your morning sleep won’t be disturbed.”
Now it has become impossible for the South Korean authorities “to have a sound sleep at daybreak,” Mr. Kwon, the North Korean official, said on Sunday.
By contrast, North Korea has seldom attacked Mr. Trump in the hopes of maintaining the good will of the American president, who has said that he and Mr. Kim fell “in love.”
Mr. Trump said that in his letter, Mr. Kim wrote that he wanted to resume dialogue with Washington as soon as the joint military drill between the United States and South Korea ended later this month.
North Korea has been less amenable to negotiating with South Korea, which it accused of failing to implement the ambitious inter-Korean economic projects that Mr. Kim and Mr. Moon agreed to pursue in meetings last year.
On Sunday, North Korea said it would not start inter-Korean talks unless South Korea halted joint military exercises with the United States or made “a plausible excuse or an explanation in a sincere manner for conducting” them.
Until then, any dialogue will be “strictly between” the North and the United States, “not between the North and the South,” Mr. Kwon said.