North Korea fired a long-range missile off its east coast on Wednesday, ahead of a meeting of the leaders of South Korea and Japan on the sidelines of a Nato summit in Lithuania to discuss rising threats, including a nuclear-armed North Korea.
The missile flew for 74 minutes for a distance of about 1,000km, Japan's chief cabinet secretary Hirokazu Matsuno said.
It was the longest flight time yet recorded by a North Korean missile and came a day after a rare meeting between the US, South Korea and Japan in Hawaii.
South Korean and US officials met immediately after the launch to reiterate their strengthened joint defence.
“We strongly condemn North Korea's launch of a long-range ballistic missile as a grave provocative act that harms the peace and stability of the Korean peninsula and the international community, and is a clear violation of UN Security Council resolutions,” the South Korean Joint Chiefs of Staff said.
Washington has been pressing Japan and South Korea to work more closely to counter growing threats from China and North Korea.
Relations between Seoul and Tokyo have long been strained over disputes dating back to Japan's occupation of Korea between 1910 and 1945.
The missile launch came after heated complaints from North Korea in recent days, accusing American spy planes of breaching its air space over economic zones.
Pyongyang also condemned a recent visit to South Korea by a US nuclear-powered cruise missile submarine.
Japan's coastguard said what was believed to be a ballistic missile appeared to have landed as of mid-morning.
It had earlier predicted the projectile would fall outside Japan's Exclusive Economic Zone in an area about 550km east of the Korean peninsula.
Mr Matsuno said the launch threatened the peace and stability of the region and the international community.
“Moreover, such ballistic missile launches violate relevant United Nations Security Council resolutions and are a serious security issue for our citizens. We have lodged a strong protest against North Korea through our embassy in Beijing,” Mr Matsuno said.
Mr Matsuno said a summit was also planned with South Korea, Australia and New Zealand.
“We will respond in close co-operation with the international community,” he said.
North Korea test-fired its first solid-fuel intercontinental ballistic missile this year and conducted a failed attempt to launch its first spy satellite on a new launch vehicle.
Security Council resolutions ban North Korea's use of ballistic missile technology, including for satellite launches.
The Security Council and several countries have imposed sanctions on Pyongyang for its missile and nuclear weapons programmes.
Analysts say commercial satellite imagery shows the North is expected to stage displays of military force, including a large parade, before a holiday on July 27 holiday that commemorates its claim to victory in the 1950-1953 Korean War against the US, South Korea and their allies.
Kim Yo-jong, the powerful sister of leader Kim Jong-un, on Tuesday accused a US military spy plane of entering the country's Exclusive Economic Zone eight times, state media KCNA reported.
Leif-Eric Easley, an international studies professor at Ewha Womans University in Seoul, said “Kim Yo-jong's bellicose statement against US surveillance aircraft is part of a North Korean pattern of inflating external threats to rally domestic support and justify weapons tests”.
“Pyongyang also times its shows of force to disrupt what it perceives as diplomatic co-ordination against it, in this case, South Korea and Japan’s leaders meeting during the Nato summit.”