SEOUL AND TOKYO - The Republic of Korea and Japan have denounced Monday's launch of four ballistic missiles by the Democratic People's Republic of Korea as a grave provocation.

In Seoul, Prime Minister Hwang Kyo-ahn, who is serving as caretaker president following the impeachment of President Park Geun-hye, called the launch a direct challenge to the international community.

And in Tokyo, Prime Minister Shinzo Abe described the move a "serious provocation".