Prime Minister Fumio Kishida of Japan was safely evacuated on Saturday after an explosion was heard just before he was scheduled to give a speech, the country’s national broadcaster said.

The episode took place late Saturday morning in the western Japanese city of Wakayama, the broadcaster, NHK, reported.

Mr. Kishida had been scheduled to give a speech in support of a lower house candidate from the ruling Liberal Democratic Party who was running in a by-election, according to NHK.

An officer at the police department in Wakayama declined to comment on Saturday.

Wakayama is near Nara, the city where former Prime Minister Shinzo Abe was assassinated during a campaign speech last July.

This is a developing story.