The Japanese government carried out Friday a drill for its emergency alert system in areas in and around the likely flight path of ballistic missiles North Korea has recently threatened to launch toward Guam.

The drill for the satellite-based J-Alert system covered 202 municipalities in nine prefectures in the Chugoku and Shikoku regions of western Japan, and tested the ability of municipalities receiving alerts to automatically broadcast them to residents.

North Korea threatened last week 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.

The drill took place in those four prefectures, plus the adjoining prefectures of Tottori, Okayama, Yamaguchi, Tokushima and Kagawa.

Some areas experienced technical glitches.

In the event of North Korea launching a missile that is feared to fly over Japan or fall within Japanese territory, on land or at sea, the J-Alert system will transmit information to areas along the path of the missile.

Under the system, alert texts received from the central government are to be transmitted to outdoor loudspeakers also used for sending alerts on natural disasters, to mobile phones, and to cable TVs in the municipalities.

Warnings may also be issued for people in at-risk areas to take shelter underground or in robust buildings.