Japan's National Police Agency chief said on Thursday he wanted to resign to take responsibility for the shooting of former prime minister Shinzo Abe in July.
The remarks at a press conference by Itaru Nakamura, whose agency is in charge of Japan's police, represent the highest-profile fallout of Abe's assassination.
Security in the western city of Nara on July 8, the day of the shooting, had been widely seen as insufficient, experts have said.
Bodyguards could have saved Abe by shielding him or pulled him from the line of fire in the 2.5 seconds between a missed first shot and the second, fatal round of gunfire, eight security experts who reviewed the footage have told Reuters.
Japanese officials, including Prime Minister Fumio Kishida, have acknowledged flaws in the security around Abe's appearance at the election campaign event.
The National Police Agency previously told Reuters the killing had been the result of police failing to fulfil their responsibility, adding that it had set up a team to review security and protection measures and evolve preventive steps.