North Korea launched at least three ballistic missiles eastward Thursday morning, the Japanese government said, adding one of them may have been an intercontinental ballistic missile potentially capable of reaching the continental United States.The Japanese government initially issued a J-Alert warning that one of the North Korean missiles was on course to fly over the main island of Honshu, but it later corrected the announcement, saying the projectile had disappeared from radar over the Sea of Japan.There is growing concern that North Korea may conduct its seventh nuclear test and first since September 2017 in the run-up to the U.S. midterm elections next week.The launches came a day after North Korea fired about 100 artillery projectiles and more than 20 short-range ballistic and other missiles, one of which fell on the south side of the de facto maritime border for the first time since the Korean Peninsula was divided.In the wake of the J-Alert warning, the second in a month, shinkansen bullet train services in central Japan were briefly suspended, according to operator East Japan Railway Co.Related coverage:N. Korea fires missiles, 1 flies across maritime border for 1st time"