The breakdown of the Hanoi summit was considered a huge embarrassment for Mr. Kim. He took a 65-hour-long train ride to meet Mr. Trump in Hanoi and had to return home without a badly needed relief from sanctions. Following the breakdown, satellite imagery showed new activities at some of the North’s long-range rocket test and missile development sites.
The White House had no immediate comment to the test.
Several days ago, appearing with South Korea’s president, Mr. Trump for the first time suggested he might be willing to entertain a “step-by-step” deal to denuclearization — contradicting his own senior aides, who had been insisting in public comments and private briefings to reporters that only a full dismantlement of the North’s nuclear weapons, missiles and facilities would result in the lifting of sanctions.
At the meeting in Hanoi, the second between the two leaders who first met in Singapore in June last year, Mr. Trump had proposed exactly that grand bargain: North Korea would get rid of its entire nuclear weapons arsenal, as well the material and facilities needed to build and test the weapons, in exchange for an end to the American-led sanctions squeezing its economy.
Mr. Kim put forth a much more modest bargain. The North would dismantle the Yongbyon nuclear complex, an aging facility at the heart of the nuclear program, for an end to the sanctions most damaging to its economy, those enacted since 2016.
Both sides walked away, and the summit collapsed.
In a speech earlier this year, Mr. Kim warned that his country might take a “new way” of protecting its interest if the United States insisted on enforcing sanctions.
During Thursday’s test of the weapon, which was conducted by the North’s Academy of Defense Science, Mr. Kim said its development “serves as an event of very weighty significance in increasing the combat power of the People’s Army,” the North Korean news agency said.
The Defense Ministry of South Korea did not immediately comment on the North’s latest weapon test. But officials there said the test of a “tactical weapon” indicated that Mr. Kim did not go so far as violating his own moratorium on nuclear and long-range ballistic missile tests, while still showing his growing impatience with Washington.