A man accused of killing former Japanese prime minister Shinzo Abe has pleaded guilty on the first day of his trial.

Tetsuya Yamagami, 45, told a court in the capital Tokyo that "everything is true", according to local media.

Yamagami - also facing charges over arms control law violations - used a homemade gun to shoot Abe during a politcal campaign event in the western city of Nara in 2022.

Abe - who was known for his hawkish foreign policy and a signature economic strategy that popularly came to be known as "Abenomics" - was shot several times, and died in hospital later the same day.

Yamagami is reported to have previously told investigators he targeted Abe because he blamed the 67-year-old for allegedly promoting the Unification Church, which he said had bankrupted his mother.