Biden 'deeply saddened' by assassination of former Japanese premier

US President Joe Biden said on Friday he was "deeply saddened" by the assassination of former Japanese Prime Minister Shinzo Abe, and offered condolences to his family.

"I am stunned, outraged, and deeply saddened by the news that my friend Abe Shinzo, former Prime Minister of Japan, was shot and killed while campaigning," said Biden in a statement.

"This is a tragedy for Japan and for all who knew him," he said.

Biden said he closely worked with Abe, and called him a "champion of the alliance" between the two nations.

"The longest serving Japanese Prime Minister, his vision of a free and open Indo-Pacific will endure," said Biden, noting that he was killed while engaging in the work of democracy.

"While there are many details that we do not yet know, we know that violent attacks are never acceptable and that gun violence always leaves a deep scar on the communities that are affected by it," he said.

"The United States stands with Japan in this moment of grief. I send my deepest condolences to his family," he added.

Abe, 67, was delivering a speech at a political event on a street in the western Japanese city of Nara when he was "shot from behind” by a person who has now been arrested.

The former prime minister was pronounced dead at 5.03 p.m. local time (0803GMT) at the hospital.