SEOUL, South Korea (AP) — Residents in northern Japan were rattled Thursday morning by alarms blaring from mobile phones, radios and public loudspeakers after North Korea fired an intercontinental ballistic missile above its eastern waters, adding to a recent barrage of provocative weapons demonstrations that officials say may culminate with a nuclear test in coming weeks.

The ICBM test, which was followed by two short-range ballistic launches into the sea, was swiftly condemned by neighbors and the United States, which said it’s willing to take “all necessary measures” to ensure the safety of the American homeland and allies South Korea and Japan.

The Biden administration also warned of unspecified “additional costs and consequences” if the North goes on to detonate a nuclear test device for the first time since September 2017.

The launches are the latest in a series of North Korean weapons tests in recent months that have raised tensions in the region. They came a day after Pyongyang fired more than 20 missiles, the most it has fired in a single day ever.

South Korea’s Joint Chiefs of Staff said it detected the North firing an ICBM from an area near its capital Pyongyang around 7:40 a.m. and then firing two short-range missiles an hour later from the nearby city of Kacheon that flew toward its eastern waters.

The longer-range missile appeared to be fired on a high angle, possibly to avoid entering the territory of neighbors, reaching a maximum altitude of 1,920 kilometers (1,193 miles) and traveling around 760 kilometers (472 miles), according to South Korea’s military.

It wasn’t immediately clear whether the launch was successful.

Japan’s Defense Minister Yasukazu Hamada announced similar flight details but said that his military lost track of the weapon after it “disappeared” in skies above waters between the Korean Peninsula and Japan.

Choi Yong Soo, a South Korean Navy captain who handles public affairs for Seoul’s Defense Ministry, didn’t answer directly when asked whether the military believes the launch might have failed with the missile exploding in midair, saying that the test was still being analyzed.

Citing anonymous military sources, South Korea’s Yonhap news agency reported that the missile possibly failed to maintain normal flight following a stage separation.

The Japanese government initially feared the ICBM would fly over its northern territory but later adjusted its assessment. Japanese Chief Cabinet Secretary Hirokazu Matsuno said the alerts were based on a trajectory analysis that indicated a flyover.

The office of Japanese Prime Minister Fumio Kishida broadcast the “J-Alert” warnings through television, radio, mobile phones and public loudspeakers to residents in the northern prefectures of Miyagi, Yamagata and Niigata, instructing them to go inside firm buildings or underground. Niigata is home to seven nuclear reactors managed by the Tokyo Electric Power Company, although they are currently all offline.

There have been no reports of damage or injuries from areas where the alerts were issued. Bullet train services in those regions were temporarily suspended following the missile alert before resuming shortly. Kishida condemned the North's launches and said officials were analyzing the details of the weapons.

The office of South Korean President Yoon Suk Yeol said his national security director Kim Sung-han discussed the launches during an emergency security meeting where members talked about plans to strength the country’s defense in conjunction with its alliance with the United States.

The office said South Korea will maintain its combined military exercises with the United States in response to North Korea’s intensifying testing activity, which it said would only deepen the North’s international isolation and unleash further economic shock on its people.

Adrienne Watson, a spokesperson for the U.S. National Security Council, issued a statement saying the United States strongly condemns the North’s ICBM test and that President Joe Biden and his national security team are assessing the situation in close coordination with allies and partners.

“This launch, in addition to the launch of multiple other ballistic missiles this week, is a flagrant violation of multiple UN Security Council resolutions and needlessly raises tensions and risks destabilizing the security situation in the region,” Watson said.

She said the United States will take all necessary measures to ensure the security of the American homeland and allies South Korea and Japan.

One of the more than 20 missiles North Korea shot on Wednesday flew in the direction of a populated South Korean island and landed near the rivals’ tense sea border, triggering air raid sirens and forcing residents on Ulleung island to evacuate. South Korea quickly responded by launching its own missiles in the same border area.

Those launches came hours after North Korea threatened to use nuclear weapons to get the U.S. and South Korea to “pay the most horrible price in history” in protest of ongoing South Korean-U.S. military drills that it views as a rehearsal for a potential invasion.

North Korea has been ramping up its weapons demonstrations to a record pace this year. It has fired dozens of missiles, including its first demonstration of intercontinental ballistic missiles since 2017, as it exploits the distraction created by Russia’s war in Ukraine and a pause in diplomacy to push forward arms development and dial up pressure on the United States and its Asian allies.

The North has punctuated its tests with an escalatory nuclear doctrine that authorizes preemptive nuclear attacks over a variety of loosely defined crisis situations. U.S. and South Korean officials say North Korea may up the ante in the coming weeks with its first detonation of a nuclear test device since September 2017.

U.S. Secretary of State Antony Blinken held a telephone call with South Korean Foreign Minister Park Jin over Wednesday’s missile launches, including the one that “recklessly and dangerously” landed near the South Korean coastline, and stressed the “ironclad” U.S. commitment to the security of its ally, according to their offices.

State Department spokesperson Ned Price also addressed concerns about possible North Korean preparations for another nuclear test, which would be its seventh overall. Experts say such tests could possibly bring North Korea a step closer to its goal of building a full-fledged arsenal threatening regional U.S. allies and the American mainland.

“Should it go forward with a seventh nuclear test there would be additional costs and consequences,” Price said, noting that the test would be a “dangerous, reckless, destabilizing act.”

North Korea last flew a missile over Japan in October in what it described as a test of a new intermediate-range ballistic missile, which experts say potentially would be capable of reaching Guam, a major U.S. military hub in the Pacific. That launch forced the Japanese government to issue evacuation alerts and pause train services.

Experts say North Korea is escalating a brinkmanship aimed at forcing the United States to accept the idea of the North as a nuclear power and negotiating economic and security concessions from a position of strength.

Nuclear talks between Washington and Pyongyang have been stalled since early 2019 over disagreements in exchanging the release of crippling U.S.-led sanctions against the North and the North’s denuclearization steps.

The North has so far ignored the Biden administration’s calls for open-ended talks, insisting that Washington should first discard its “hostile” policy, a term North Korea mainly uses to describe sanctions and combined U.S.-South Korea military exercises.

White House National Security Council spokesperson John Kirby on Wednesday underscored that the Biden administration has repeatedly sought to reach out to North Korean officials through diplomatic channels and has made clear “we’re willing to sit down with North Korea without precondition to discuss the denuclearization of the peninsula.”

Yamaguchi reported from Tokyo. AP writers Aamer Madhani and Ellen Knickmeyer contributed to the story from Washington.