North Korea fired a ballistic missile towards the sea on Wednesday in a display of its expanding military capabilities hours after saying it would resume nuclear diplomacy with the United States this weekend.
South Korean military officials said the missile was fired from North Korea's eastern waters, suggesting it may have been submarine-launched.
But defence officials in Seoul did not officially disclose whether the missile was fired from a submarine, a barge or any other possible platform.
North Korea having the ability to launch missiles from submarines would be alarming because such weapons are harder to detect in advance.
According to Seoul's Joint Chiefs of Staff, the missile flew about 450 kilometers at the maximum attitude of 910 kilometers before landing between the Korean Peninsula and Japan. Seoul said South Korean and US authorities were analyzing launch data.
Japanese chief cabinet secretary Yoshihide Suga earlier said Pyongyang fired two ballistic missiles from the country's east coast, and one of them appeared to have landed inside Japan's exclusive economic zone. There were no reports of damage to Japanese vessels or aircraft, he said. The North had not fired a weapon that reached inside Japan's EEZ since November 2017 at the height of an unusually provocative run in nuclear and missile tests.
Japanese Prime Minister Shinzo Abe condemned the launches and said they violate UN resolutions against the North.
"We will continue to cooperate with the US and the international community and do the utmost to maintain and protect the safety of the people as we stay on alert," Mr Abe said.
The launches, which were the North's ninth round of weapons tests since late July, came hours after a senior North Korean diplomat said it has agreed to resume working-level nuclear negotiations this weekend with Washington.
After supervising a testing firing of what the North described as a "newly developed super-large multiple rocket launcher" last month, North Korean leader Kim Jong-un was quoted by state media as saying that the system would require a "running fire test" to complete its development.
North Korea could also be demonstrating its displeasure over South Korea displaying for the first time some of its newly purchased US-made F-35 stealth fighter jets at its Armed Forces Day ceremony on Tuesday.
The North has called the F-35 purchases a grave provocation that violate recent inter-Korean agreements aimed at lowering military tensions.
Kim Dong-yub, an analyst from Seoul's Institute for Far Eastern Studies and a former military official who participated in inter-Korean military talks, said the North's launch was clearly aimed at increasing pressure on Washington ahead of planned weekend talks where it might demand concessions on US-led sanctions against its crippled economy.
Nuclear negotiations halted following a February summit between Mr Kim and President Donald Trump in Vietnam that broke down after the US rejected North Korean demands for broad sanctions relief in exchange for partially surrendering its nuclear capabilities.
North Korea's subsequent belligerent rhetoric and recent short-range weapons tests have been seen as an attempt to gain leverage before resuming the negotiations.
In a statement released through state media, Choe Son-hui, North Korea's first vice minister of foreign affairs, said the two nations will have preliminary contact on Friday before holding working-level talks on Saturday. She did not say where it would take place.
"It is my expectation that the working-level negotiations would accelerate the positive development of the DPRK-US relations," Ms Choe said.
State Department spokeswoman Morgan Ortagus, who is travelling with Secretary of State Mike Pompeo in Rome, said later she did not have further details to share about the meeting.
Last month, North Korea praised Mr Trump for suggesting Washington may pursue an unspecified "new method" in the negotiations. North Korea also has welcomed Trump's decision to fire former National Security Adviser John Bolton, who advocated a "Libya model" of unilateral denuclearisation as a template for North Korea.