Security officials were seen tackling the man in a grey T-shirt and beige trousers.
Japanese former Prime Minister Shinzo Abe died after being shot during a political event earlier today. The man who attacked Abe was "dissatisfied" with him and wanted to kill him, local media reported, citing police sources.
The 41-year-old, a former member of the Japanese Maritime Self-Defense Force, opened fire at Abe with an apparently homemade gun. Explosives were found at the shooter's house, officials said.
Shinzo Abe was making a campaign speech outside a train station in the western city of Nara when two shots rang out. Security officials were then seen tackling the suspect in a grey T-shirt and beige trousers.
A photograph of Abe showed him lying face-up on the street by a guardrail, blood on his white shirt. People were crowded around him, one administering heart massage.
Prime Minister Fumio Kishida condemned the shooting in the "strongest terms" while Japanese people and world leaders expressed shock at the assassination attempt in a country in which political violence is rare and guns are tightly controlled.
"Everything that can be done is being done to revive him. I'm praying from the depths of my heart that his life will be saved," Kishida told reporters, adding he was not aware of any motive.
Senior Japanese politicians are accompanied by armed security agents but often get close to the public, especially during political campaigns when they make roadside speeches and shake hands with passersby.