JEJU, South Korea — When North Korea launched a volley of projectiles off its east coast on Saturday, it sought to escalate the pressure on President Trump to return to the negotiating table with a compromise on easing sanctions, analysts said, by signaling that it could scuttle his biggest diplomatic achievement with the North.
Saturday’s weapons tests were the most serious by the North since the country launched its Hwasong-15 intercontinental ballistic missiles in November 2017. Although North Korea has not gone so far as to renege on its moratorium on nuclear and ICBM tests, which its leader, Kim Jong-un, announced last year, the Saturday launch indicated that Mr. Kim was toying with the idea of lifting the moratorium, analysts said.
Mr. Trump has repeatedly described the moratorium as his biggest achievement on North Korea, citing it as proof that his diplomacy with Mr. Kim has been working. The leaders have met twice: first in Singapore in June and again in Hanoi, Vietnam, in February.
“Today’s provocation means that Kim Jong-un is becoming increasingly pessimistic” that he could work out a settlement with Mr. Trump, said Lee Byong-chol, a North Korea expert at Kyungnam University’s Institute of Far Eastern Studies in Seoul.
“There may be some minor adjustments in the North’s behavior depending on how the U.S. responds, but in the long term, it seems increasingly clear that Kim has decided to go his own way.”
American and South Korean authorities were analyzing flight data from the tests to identify what types of weapons were launched, the office of President Moon Jae-in of South Korea said. South Korean officials said the “short-range” projectiles flew only 42 to 124 miles off the North’s east coast, ruling out the possibility that the country had resumed tests of intermediate- or intercontinental-range ballistic missiles.
Those tests had prompted Mr. Trump to threaten to rain “fire and fury” down on the North and had raised the chance of military conflict on the Korean Peninsula in 2017.
South Korean officials said they were also looking into the possibility that the projectiles were short-range Scud missiles or rockets from multiple-launch tubes — or both.
The potential implications of any short-range missile tests could be far-reaching. The short-range weapons were developed mainly to target South Korea and United States military bases there. North Korea also tested weapons in November last year and again last month. But those weapons were largely considered tactical types with very small ranges.
By gradually increasing the ranges of weapons tests in recent weeks, Mr. Kim appeared to be carefully calibrating his options with Mr. Trump. Firing short-range weapons may be an attempt to force a breakthrough in the stalled negotiations with Washington while not provoking Mr. Trump too far, analysts said.
The Hanoi meeting in February abruptly ended when Mr. Trump rejected Mr. Kim’s suggestion that Washington lift the most painful of sanctions imposed against his country since 2016 in return for a partial dismantlement of its nuclear weapons program. Mr. Trump wanted the quick rollback of the North’s entire nuclear weapons program.
After returning home without badly needed relief from sanctions, Mr. Kim said he would give Mr. Trump until the end of the year to offer a new proposal.
But any weapons test by North Korea increases uncertainty. Mr. Kim may be deliberately provoking Mr. Trump into lashing out with fiery rhetoric so that the North could use that as an excuse to resume nuclear or long-range missiles, analysts said.
“Pyongyang is saying plainly that without progress in the talks, tests are likely to resume in full,” said Adam Mount, a senior fellow at the Federation of American Scientists. “While it’s clear that this is meant to send a more restrained signal than a return to tests of longer range missiles that Kim Jong-un voluntarily paused, what’s not clear is whether the president will draw that distinction.”
Mr. Trump’s initial response suggested that the tests had not dented his optimism on negotiations with North Korea.
“I believe that Kim Jong Un fully realizes the great economic potential of North Korea, & will do nothing to interfere or end it,” he wrote on Twitter on Saturday. “He also knows that I am with him & does not want to break his promise to me. Deal will happen!”
Even so, the tests placed further strain on Mr. Moon’s flagship policy of facilitating dialogue between Washington and Pyongyang.
In Seoul, Mr. Moon’s office expressed “serious concern” that North Korea was violating the spirit of the inter-Korean agreement to ease military tensions that was signed when the South Korean president visited Pyongyang in September. It urged North Korea to return to the negotiating table with Washington.
Mr. Moon’s government had hoped to use the United Nations’ latest report of food shortages in North Korea to urge Washington to allow aid shipments to its neighbor, hoping that would help restart the stalled dialogue, said Woo Jung-yeop, a North Korea expert at the Sejong Institute in South Korea.
“It has become much more difficult for the South to push for food aid as an incentive for North Korea,” he said.
Japan’s initial response to the launches was muted, as the tests occurred just as the new emperor, Naruhito, was greeting the public for the first time on Saturday morning at the imperial palace in Tokyo. The Defense Ministry put out a notice saying that the projectiles had not landed in Japanese territorial waters.
Like the rest of the region, Japan was waiting to see how Mr. Trump reacted to the provocations. Earlier in the week, Prime Minister Shinzo Abe said that he would be willing to meet Mr. Kim on an “unconditional” basis, retreating from a more hawkish position in which the Japanese leader had indicated that he would meet with the North Korean dictator only once he had taken concrete steps toward denuclearization and agreed to resolve a dispute over Japanese citizens abducted by North Korea in the 1970s and ’80s.
Other analysts warned against reading too much into the North’s tests on Saturday, calling them as much a sign of desperation as a show of force. Since 2016, Washington has led a campaign at the United Nations Security Council to strangle the North’s economy by banning all its key exports, including coal and textiles, as well as drastically cutting its oil imports.
“They are in such a desperate economic situation,” said Bonji Ohara, a senior fellow at the Sasakawa Peace Foundation in Japan.
Mr. Kim’s message is “the U.S. must compromise, not North Korea. That’s why they fired relatively short-range rockets this time,” said Hideshi Takesada, a professor of international relations and security issues with a focus on the Korean Peninsula at the Graduate School of Takushoku University.
The short-range weapons tested on Saturday were “more about repelling an invasion than starting a war,” said Melissa Hanham, a North Korean weapons expert at the One Earth Future Foundation. “Probably what is happening is some kind of testing of a unit to make sure that everyone is prepped and ready, and it is probably somewhat routine.”
Ankit Panda, an adjunct senior fellow at the Federation of American Scientists, which is based in Washington, said that while Mr. Kim was sending a message to Washington that “the door for diplomacy is not open forever,” he was also likely to be signaling strength to his domestic population.
“He was embarrassed in Hanoi,” said Mr. Panda, referring to the failed summit meeting between Mr. Kim and Mr. Trump. “So he needs to continue to show people in North Korea that he’s still a strong leader.”