Japanese Prime Minister Shinzo Abe condemned a North Korean missile test on Wednesday, according to media, as reports emerged of a possible second test by Pyongyang.
"If it were a ballistic missile launch, it clearly cannot be tolerated," Abe said, broadcaster NHK reported.
"We will thoroughly analyse the case, and will coordinate with the international community, including South Korea and the United States," Abe said, speaking after the first launch was reported.
North Korea conducted two back-to-back tests of a powerful new medium-range missile on Wednesday, with at least one launch ending in failure, South Korea`s Defence Ministry said.
The first test shortly before 6:00 am (2100 GMT Tuesday) was deemed to have failed, but the ministry said it was unable to confirm the status of a second launch detected two hours later from the same location on the east coast.