North Korea on Sunday launched its most powerful missile since late 2017, potentially marking an end to nearly four years of leader Kim Jong Un's self-imposed moratorium on long-range tests.

Japan rushed to analyze the launch, the nuclear-armed country's seventh round of weapons tests this month, with Chief Cabinet Secretary Hirokazu Matsuno, the government's top spokesman, convening two hurried news conferences Sunday morning.

"Considering that the ballistic missile reached an altitude of about 2,000 kilometers and flew about 800 km, it's possible that it was a ballistic missile of medium or longer range," Matsuno said.