TOKYO — The Japanese government held its first-ever drill Friday to protect citizens in case a ballistic missile is launched toward Japan.

More than 100 residents and schoolchildren of the coastal city of Oga in northern Japan participated in the drill. Loudspeakers warned them of a possible missile threat and urged them to seek shelter indoors because missile parts might fall.

The drill assumed a scenario of a hypothetical country firing a missile that falls into Japanese territorial waters off the coast of Akita prefecture. It came amid increasing missile threats from North Korea.

Earlier this month, North Korea fired four missiles, of which three landed in the 200-nautical mile offshore area where Tokyo has sovereign rights to explore and exploit resources.

Chief Cabinet Secretary Yoshihide Suga told reporters "it is imperative to raise the public's awareness" about how they should respond in case of a missile threat.

The drill began with a government alert issued at 9:30 a.m. warning of a possible missile launch.

Municipal officials then used loudspeakers and emails to urge residents to seek cover at designated evacuation centers.

During the drill, schoolchildren and others who were outside sought shelter inside a school building or a community center.