Japanese Prime Minister Fumio Kishida was rushed to a safer place after a blast was heard near the area where Kishida is delivering a speech.
National broadcaster NHK said that the prime minister was safe, and a person was detained at the scene at a port in Wakayama in western Japan.
In a BBC report, a witness saw a man throwing something, followed by smoke, while another said they heard a big bang.
No injuries were reported.
“Police are investigating details, but I’d like to apologize for worrying many people and causing them trouble,” Kishida said.