SEOUL, South Korea (AP) -- North Korea on Tuesday conducted its longest-ever weapons test, a nuclear-capable ballistic missile that flew over Japan and could reach the U.S. Pacific territory of Guam and beyond, forcing the Japanese government to issue evacuation alerts and halt trains.
The South Korean and U.S. militaries responded by launching fighter jets which fired weapons at a target off South Korea's west coast in a show of strength against North Korea.
The North Korean missile launch was its most provocative weapons demonstration this year, as it pushes to develop a fully fledged nuclear arsenal capable of threatening the U.S. mainland and its allies with the goal of wresting concessions from those countries, some experts say.
North Korea has test-fired about 40 missiles over about 20 different launch events this year as its leader, Kim Jong Un, refuses to return to nuclear diplomacy with the United States.
The United States strongly condemned North Korea's "dangerous and reckless decision" to launch what it described as a "long-range ballistic missile" over Japan.
"The United States will continue its efforts to limit (North Korea's) ability to advance its prohibited ballistic missile and weapons of mass destruction programs, including with allies and U.N. partners," National Security Council spokesperson Adrienne Watson said in a statement.
South Korea and Japan earlier said the missile had an intermediate or longer range. If the launch involved a long-range missile, it could be a test of a weapon capable of targeting the U.S. homeland, some experts say.
The launch is the fifth round of weapons tests by North Korea in the past 10 days. The testing spree is an apparent response to two sets of military drills -- one between Washington and Seoul and the other involving Washington, Seoul and Tokyo -- off the Korean Peninsula's east coast last week.
North Korea regards such drills involving the United States as an invasion rehearsal. It was expected to react strongly this time because both exercises involved a U.S. aircraft carrier, which North Korea views as more provocative.
Japanese authorities alerted residents in its northeastern regions to evacuate to shelters, in the first "J-alert" since 2017 when North Korea fired an intermediate-range Hwasong-12 missile twice over Japan in a span of weeks during a previous run of weapons tests.
Trains were suspended in the Hokkaido and Aomori regions until the government issued a notice that the North Korean missile appeared to have landed in the Pacific. In Sapporo city, the prefectural capital of Japan's northernmost main island of Hokkaido, subways were also temporarily halted, with stations packed with morning commuters.
Japanese Prime Minister Fumio Kishida told reporters the launch "is a reckless act and I strongly condemn it."
South Korean President Yoon Suk Yeol said North Korea's "reckless nuclear provocations" would meet a stern response from the South and the broader international community. His military separately warned that North Korea's repeated missile launches would deepen its international isolation and prompt Seoul and Washington to bolster their deterrence capacities.
Later Tuesday, four U.S. F-16 fighter jets and four South Korean F-15s conducted a joint strike drill in which one of the South Korean planes fired two precision-guided Joint Direct Attack Munition bombs into an island target. The exercise was aimed at demonstrating the allies' ability to accurately strike North Korean targets with "overwhelming force," the South Korean Joint Chiefs of Staff said.
According to South Korean and Japanese estimates, the North Korean missile fired from the its northern province bordering China traveled 4,500-4,600 kilometers (2,800-2,860 miles) at a maximum altitude of 970-1,000 kilometers (600-620 miles). Japanese Defense Minister Yasukazu Hamada said it landed in the Pacific about 3,200 kilometers (1,990 miles) off the northern Japanese coast and that there were no reports of damage to Japanese aircraft or ships.
South Korea's Defense Ministry said the missile flew farther than any other weapon fired by North Korea. Before Tuesday's launch, the 3,700-kilometer (2,300 miles) -long flight of a Hwasong-12 in 2017 was North Korea's longest. It has previously tested intercontinental ballistic missiles at steep angles so they flew shorter to avoid neighboring countries.
The missile's flight distance shows it has enough range to hit Guam, home to U.S. military bases that have sent advanced warplanes to the Korean Peninsula in shows of force during past periods of tension with North Korea. In 2017, North Korea threatened to make "an enveloping fire" near Guam with Hwasong-12 missiles amid rising animosities with the then-Trump administration.
North Korea last test-fired a Hwasong-12 missile in January. At the time, it said the launch was meant to verify the overall accuracy of the weapon.
Lee Choon Geun, an honorary research fellow at South Korea's Science and Technology Policy Institute, said Tuesday's launch of a suspected Hwasong-12 missile would demonstrate a capacity that "truly places Guam within striking distance." He said North Korea likely wanted to confirm the missile's operational capabilities as it is being mass-produced.
Kim Dong-yub, a professor at Seoul's University of North Korean Studies, said North Korea could have tested the Hwasong-12 again, or even an intercontinental ballistic missile, closer to what would be a normal ballistic trajectory but shorter than its full range. If it was an ICBM, the purpose of the launch would be to test whether the warhead could survive the harsh conditions of atmospheric reentry, Kim said.
The missiles fired during the past four rounds of launches were short-range and fell in the waters between the Korean Peninsula and Japan. Those missiles are capable of hitting targets in South Korea.
Heo Tae-keun, South Korea's deputy minister of national defense policy, told lawmakers Tuesday that North Korea is preparing to test a new liquid-fueled ICBM and a submarine-launched ballistic missile as well. He said North Korea also maintains a readiness to conduct a nuclear test in what would be its first such bomb detonation in five years and its seventh in total.
Last month, North Korea adopted a new law authorizing the preemptive use of nuclear weapons in some cases, a move that showed its increasingly aggressive nuclear doctrine. Last Saturday, Yoon warned of a "resolute, overwhelming response" from South Korean and U.S. militaries if North Korea uses nuclear weapons.
Some foreign experts say North Korea needs to master a few remaining technologies to acquire functioning nuclear-armed missiles. Each new test pushes it closer to being able to reach the U.S. mainland and its allies with a host of missiles of varying range.
Some experts say North Korean leader Kim will eventually will return to diplomatic talks and use his enlarged arsenal to pressure Washington to accept his country as a nuclear state, a recognition that he thinks is necessary to win the lifting of international sanctions and other concessions.