Former Japanese prime minister Shinzo Abe is in a “state of cardiopulmonary arrest”, police have said, after collapsing while making a speech in the western city of Nara amid reports of gunfire.

NHK, Japan’s public broadcaster, said Abe – the country’s longest-serving prime minister until he resigned in 2020 – fell to the ground and appeared to be bleeding from the chest after being shot from behind with a shotgun on Friday morning.

NHK quoted firefighters as saying he showed no vital signs.

Media reports quoted police as saying that the weapon thought to have been used in the attack was homemade. A photograph showed two cylindrical metal parts that appeared to have been heavily bound with black tape lying on the road near the scene.

NHK said a suspect, named by police as Tetsuya Yamagami, a 41-year-old resident of Nara, had been taken into custody but provided no further details.