A loud explosion has been heard at an outdoor event being attended by Japan's prime minister, according to local reports.

Japanese media claims a pipe-like object was thrown at Fumio Kishida after he began a speech at a port in the city of Wakayama - and he was subsequently evacuated.

Image: A man was held to the ground by police at the scene. Pic: Kyodo News/AP A man, on the ground, is caught after what appeared to be a smoke bomb was thrown at a port in Wakayama, western Japan Saturday, April 15, 2023. Japan...s NHK television reporte

According to NHK, he took cover and remained safe during the incident - and no other injuries have been reported.

Footage from the scene showed a man being pressed to the ground by uniformed officers as crowds ran away. Police later confirmed that an arrest had been made.

Image: The PM was evacuated from the scene. Pic: Yomiuri Shimbun/AP

Last July, former prime minister Shinzo Abe - the country's longest-serving leader - died after being shot at close range while making a campaign speech outside a train station.

Mr Kishida was visiting the area to cheer one of his party's candidates, who is taking part in a local election.