In Tokyo, Yoshihide Suga, Japan’s chief cabinet secretary, said that what was initially thought to be two missiles was actually one that split into two. One of those pieces fell inside Japan’s economic zone off its Shimane prefecture. Japan said it had no immediate reports of damage to aircraft or ships nearby.

In a series of weapons tests this year, North Korea launched new types of short-range ballistic missiles and more powerful versions of multi-tube rocket launchers. Its new weapons have alarmed South Korea and Japan because they have longer ranges and are believed to be more difficult to intercept by missile defense systems.

North Korea’s latest test came a day after the South commemorated Armed Forces Day, during which it displayed newly acquired F-35 stealth jets. By showcasing the state-of-the-art combat aircraft, South Korea reinforced its commitment to its defense, even as it was trying to engage North Korea in dialogue. The North has accused the South of raising tensions through its purchase of the American jets.

Wednesday’s launch marked the first time a projectile fired by North Korea reached the Japanese exclusive economic zone since the North resumed its missile tests this year after a 17-month hiatus. The last North Korean missile that fell into Japan’s exclusive economic zone was its Hwasong-15 intercontinental ballistic missile, launched in November 2017.

“We are aware of reports of a possible North Korean missile launch,” a senior Trump administration official said Tuesday night in Washington. “We are continuing to monitor the situation and consulting closely with our allies in the region.”

Just hours before the latest test, officials in North Korea and the United States said that they had agreed to resume official talks over the nuclear weapons program — the first substantive discussions since the two nations’ summit meeting in Hanoi in February failed to produce an accord.

Choe Son-hui, first vice foreign minister of North Korea, said her government and Washington had agreed to establish preliminary contact on Friday, to be followed by official, working-level negotiations on Saturday. The State Department confirmed the meeting, which Secretary of State Mike Pompeo had recently hinted was coming soon.