South Korea's Joint Chiefs of Staff says North Korea launched 3 short-range ballistic missiles on Wednesday morning from the eastern city of Wonsan toward the Sea of Japan.
Japanese government officials say they are also monitoring the situation.
The officials say the projectiles appears to have landed in the ocean outside Japan's exclusive economic zone.
Japan's Defense Ministry says North Korea has been ramping up its ballistic missile program.
They included an intermediate-range ballistic missile that flew over Japan on October 4.