Former Japanese Prime Minister, Shinzo Abe, is said to be in a "grave condition" after being shot in the chest overnight.
It happened in the western city of Nara while he was campaigning for a parliamentary election, and has since been airlifted to hospital.
Taoiseach Micheal Martin has joined world leaders in voicing their shock at the attack.
North Asia correspondent for the Sydney Morning Hearld, Eryk Bagshaw is in Japan - he says a suspect has been arrested.
"A 41 year old has been arrested. He was taken immediately after the shooting, he was tackled by Abe's security detail and dragged from the scene and arrested - he's now been charged with attempted murder.
"He's actually a former member of Japan's self defence forces, so a military man.
"It's still unclear what his connection with Shinzo Abe is."
