SEOUL — North Korea fired an unidentified projectile off its east coast on Friday, hours after it warned of “stronger and certain reaction” if the United States helped impose more sanctions on the North in response to its recent series of missile tests.
The South Korean military said its analysts were studying the trajectory and other flight data from the launch to learn more. When North Korea launches a missile, the South’s military usually calls it “an unidentified projectile” before it relates more details.
Earlier on Friday, the North’s Foreign Ministry issued a statement denouncing a proposal by the United States that the U.N. Security Council place fresh sanctions on North Korea following its six ballistic and other missile tests since September 2021.
The tit for tat between North Korea and the United States raised tensions at a sensitive time in the region, as China geared up for hosting the Winter Olympics in Beijing next month and South Korea for its presidential election on March 9.
Separately on Wednesday, the Biden administration blacklisted five North Korean officials active in Russia and China who Washington said were responsible for procuring goods for North Korea’s weapons of mass destruction and ballistic missile-related programs.
North Korea resumed testing missiles in September after a six-month hiatus. It has since conducted at least six missile tests, which involved a long-range strategic cruise missile, ballistic missiles rolled out of mountain tunnels and a mini submarine-launched ballistic missile. In two tests this month, it launched what it called hypersonic ballistic missiles with detachable gliding warheads that made them harder to intercept because they could change course during flight.
All the tests violated U.N. Security Council resolutions that banned North Korea from developing or testing ballistic missile technologies or technologies used to make and deliver nuclear weapons. But the North’s Foreign Ministry insisted on Friday that it was exercising “its right to self-defense” and that the missile tests were “part of its efforts for modernizing its national defense capability.”
“The U.S. is intentionally escalating the situation even with the activation of independent sanctions, not content with referring the D.P.R.K.’s just activity to the U.N. Security Council,” the ministry said in a statement, using the acronym for the North’s official name, the Democratic People’s Republic of Korea. It added, “If the U.S. adopts such a confrontational stance, the D.P.R.K. will be forced to take stronger and certain reaction to it.”
The statement did not elaborate on North Korea’s possible future actions. But the country has resumed missile tests since meetings between its leader, Kim Jong-un, and Donald J. Trump, then president, ended without an agreement on how to roll back the North’s nuclear weapons program or when to lift sanctions.
Those tests indicated that the North was developing more sophisticated ways of delivering nuclear and other warheads to South Korea, Japan and American bases there on its shorter-range missiles, according to defense analysts. Some of the missiles it has tested since 2019 have used solid fuel and have made midair maneuvers, making them harder to intercept, the analysts said.
North Korea has not resumed testing any long-range missiles of the kind that could directly threaten the continental United States since it conducted three intercontinental ballistic missile tests in 2017. But since the Kim-Trump diplomacy collapsed, North Korea has warned that it no longer felt bound by its self-imposed moratorium on nuclear and long-range missile tests. It has since unveiled its largest-ever, still-untested ICBM during a military parade and exhibition.
During a Workers’ Party meeting in January last year, Mr. Kim vowed to make more sophisticated short-range nuclear missiles, hypersonic missiles, large ICBMs and submarine-launched long-range missiles, as well as to place military spy satellites into orbit.
On Friday, North Korea reiterated that its missile tests “did not target any specific country or force and it did not do any harm to the security of neighboring countries.” But in the test on Tuesday, the North’s hypersonic missile traversed the country from west to east and then veered to the northeast, flying over the waters between the Russian Far East and Japan toward the Pacific, according to its trajectory graphic in one of the photos released in North Korean state media.
The missile hit a target 621 miles away, the North said. And as the missile hurtled out of North Korea at up to 10 times the speed of sound, aviation regulators briefly halted flights out of some airports on the U.S. West Coast as a precaution.
It was the first missile test that Mr. Kim had attended since March 2020, according to reports in North Korean media.
The test prompted South Korea to reassure its residents this week that its military can detect and intercept the North’s new missiles.
Washington has repeatedly urged North Korea to return to talks, but the country has said it would not until it was convinced that the United States would remove its “hostile” policy, including sanctions.
China, which can veto Washington’s attempt to impose more sanctions at the Security Council, called for dialogue.
“Willful sanctions do not help resolve the Korean Peninsula issue, but only worsen the confrontational mood,” Wang Wenbin, a spokesman of the Chinese Foreign Ministry, said during a news briefing on Wednesday.