A loud explosion occurred at a western Japanese port on Saturday during Prime Minister Fumio Kishida’s visit, but there were no injuries, Japan’s NHK television reported.

Kishida was unharmed and evacuated to the Wakayama prefectural police headquarters, NHK said.

The incident comes only nine months after Kishida’s predecessor, Shinzo Abe, was assassinated while delivering a campaign speech in the western city of Nara. The assassination shocked the nation and a subsequent investigation found holes in Abe's security, and led to reinforcement of Japan's police security measures.

The attack also comes as a series of Group of Seven ministerial meetings begins this weekend ahead of the May 19-21 summit that Kishida will host in Hiroshima.

Kishida was visiting the Saikazaki port in Wakayama prefecture to cheer his ruling party's candidate in a local election. The explosion happened just before he was to begin his speech, NHK said.

A man believed to be a suspect was arrested at the scene, and NHK footage showed several uniformed and plainclothes police officers gathered around the man, pressing him to the ground and dragging him to the side.

The suspect, identified only as a young male, allegedly threw the explosive, NHK said.

One witness told NHK that she was among the crowd and saw something come flying from behind and that there was a sudden loud noise and she fled with her children. Another witness said people were screaming and that he saw someone being apprehended right before the explosion occurred.