Japanese Prime Minister Fumio Kishida was evacuated Saturday after a loud explosion was heard at a venue, national broadcaster NHK reported.
The incident took place right before he was scheduled to give a speech in Wakayama.
Fumio was uninjured and left the city, said NHK, citing sources.
Police said a suspect has been arrested who appears to have thrown a bomb at the port where the prime minister was set to give his speech.
The incident comes nine months after the assassination of former Prime Minister Shinzo Abe.