Former Japanese Prime Minister Shinzo Abe was shot while delivering a speech in the western city of Nara, according to reports.
Public broadcaster NHK said he appeared to be in cardiac arrest.
The channel said gunshots were heard and a puff of white smoke was seen as Mr Abe makes a campaign speech in front of a train station.
A reporter on site said he heard two consecutive detonations during the speech.
NHK released footage showing Mr Abe, 67, collapsed in the street, with several security guards running towards him.
A Nara City Fire Department spokesman said he was in cardiorespiratory arrest before being taken to hospital.
NHK said Mr Abe appeared to have been shot from behind, while TBS Television said he was shot in the left side of his chest and possibly also in the neck.
Chief Cabinet Secretary Hirokazu Matsuno said police arrested a man in connection with the shooting.
“A barbaric act like this is absolutely unforgivable, regardless of the reasons, and we strongly condemn it,” Matsuno said.
U.S. Ambassador Rahm Emanuel said, “The U.S. government and the American people are praying for the well-being of Abe-san, his family, and the Japanese people.”
Australian Prime Minister Anthony Albanese tweeted: “Shocking news from Japan that former Prime Minister Shinzo Abe has been
shot – our hearts go out to his family and the people of Japan at this time.”
Mr Abe served two terms as prime minister to become Japan’s longest-serving prime minister before stepping down in 2020 due to ill health.
But he remained a dominant presence on the ruling Liberal Democratic Party (LDP), controlling one of its main factions.
His protege, Prime Minister Fumio Kishida, faces an upper house election on Sunday in which analysts say he hopes to step out of Mr Abe’s shadow and define his post as prime minister.
