Abe, 67, had been delivering a speech near a train station when he was shot by an assailant at around 11.30am.
Footage broadcast by NHK showed Abe standing on a stage when a loud blast was heard with smoke visible in the air.
Police said a 41-year-old man suspected of carrying out the shooting was arrested. NHK reported that the suspect, identified as Tetsuya Yamagami, told police he was dissatisfied with Abe and wanted to kill him.
It was the first assassination of a sitting or former Japanese premier since the days of prewar militarism in the 1930s.
Speaking before Abe’s death was announced, Japanese Prime Minister Fumio Kishida condemned the shooting in the “strongest terms” while Japanese people and world leaders expressed shock at the violence in a country in which political violence is rare and guns are tightly controlled.
“This attack is an act of brutality that happened during the elections – the very foundation of our democracy – and is absolutely unforgivable,” said Kishida.
Police said the suspected shooter was a resident of Nara. The gun used in the shooting appeared to be a homemade firearm, NHK reported earlier.
Several media outlets the suspect as a former member of the Maritime Self-Defense Force. Abe’s younger brother, Defence Minister Nobuo Kishi, declined to comment on that.