Glitches surfaced in the J-Alert system Friday as the government held a test for municipalities deemed at risk from missiles North Korea is threatening to launch toward Guam.

The exercise based on the satellite-based J-Alert system covered 202 municipalities in nine prefectures in the Chugoku and Shikoku regions. It was designed to test municipalities' ability to receive missile launch alerts and automatically broadcast them to residents.

Last week, North Korea threatened to simultaneously launch four ballistic missiles toward waters near the U.S. territory of Guam, in the western Pacific. The suggested flight path would take the missiles over Shimane, Hiroshima, Ehime and Kochi prefectures.