Updated 3pm with details on shooting suspect

Japan's former prime minister Shinzo Abe died in hospital on Friday, the facility treating him confirmed, hours after being shot at a political campaign event in an attack condemned as "absolutely unforgivable".

"Shinzo Abe was transported to (the hospital) at 12:20 pm. He was in a state of cardiac arrest upon arrival. Resuscitation was administered. However, unfortunately he died at 5:03 pm," said Hidetada Fukushima, professor of emergency medicine at Nara Medical University Hospital.

The assassination of the country's best-known politician comes despite Japan's strict gun laws and with campaigning under way ahead of upper house elections on Sunday.

Japanese police later on Friday named the suspected killer of former prime minister Shinzo Abe as unemployed 41-year-old Tetsuya Yamagami, who told officers he had used a handmade gun.

"That's the suspect's assertion, and we have determined that (the gun) is clearly handmade in appearance, although our analysis is currently ongoing," a police officer in Nara region, where the assassination took place, told reporters.

Earlier Prime Minister Fumio Kishida abandoned the campaign trail and flew to Tokyo by helicopter where he addressed reporters in a voice that wavered with emotion.

"I pray that former prime minister Abe will survive," he said, condemning "a barbaric act during election campaigning, which is the foundation of democracy."

"It is absolutely unforgivable. I condemn this act in the strongest terms."

The attack came before noon in the country's western region of Nara, where Abe, 67, had been delivering a stump speech with security present, but spectators able to approach him easily.

Footage broadcast by NHK showed him standing on a stage when a man dressed in a grey shirt and brown trousers begins approaching from behind, before drawing something from a bag and firing.

At least two shots appear to be fired, each producing a cloud of smoke. The incident happened around 11.30am. 

As spectators and reporters ducked, a man was shown being tackled to the ground by security. He was later arrested on suspicion of attempted murder, reports said.

Local media identified the man as 41-year-old Tetsuya Yamagami, citing police sources, with several media outlets describing him as a former member of the Maritime Self-Defense Force, the country's navy.

He was wielding a weapon described by local media as a "handmade gun", and NHK said he told police after his arrest that he "targeted Abe with the intention of killing him".

'A large bang'

Witnesses at the scene described shock as the political event turned into chaos.

"The first shot sounded like a toy bazooka," a woman told NHK. 

"He didn't fall and there was a large bang. The second shot was more visible, you could see the spark and smoke," she added.

"After the second shot, people surrounded him and gave him cardiac massage."

Abe was bleeding from the neck, witnesses said and photographs showed. He was reportedly initially responsive but subsequently lost consciousness.

Officials from the local chapter of Abe's Liberal Democratic Party said there had been no threats before the incident and that his speech had been announced publicly.

Kishida said "no decision" had been made on the election, though several parties announced their senior members would halt campaigning in the wake of the attack.

The attack prompted international shock.

'Saddened and shocked'

Jiji said the government said a task force had been formed in the wake of the incident, and reaction was already beginning to pour in.

Andre Spiteri, Malta's ambassador to Japan, said he was "shocked and saddened".

"Prime Minister Abe was the first Japanese Prime Minister to officially visit in 2017 - and a great friend of Malta. We stand with the people of Japan during this difficult moment," he tweeted. 

Prime Minister Robert Abela condemned the "senseless act of violence" and offered his condolences to Abe's family and the people of Japan. President George Vella said he was deeply shocked, adding that he had fond memories of the state visit five years ago. 

"We are all saddened and shocked by the shooting of former prime minister Abe Shinzo," US Ambassador to Japan Rahm Emanuel said in a statement.

"The US government and American people are praying for the well-being of Abe-san, his family, and people of Japan."

Prime Minister Fumio Kishida's special advisor Gen Nakatani told reporters "terror or violence can never be tolerated," Jiji reported.

Abe, Japan's longest-serving prime minister, held office in 2006 for one year and again from 2012 to 2020, when he was forced to step down due to the debilitating bowel condition ulcerative colitis.

He is a hawkish conservative who pushed for the revision of Japan's pacifist constitution to recognise the country's military and has stayed a prominent political figure even after stepping down.

Japan has some of the world's toughest gun-control laws, and annual deaths from firearms in the country of 125 million people are regularly in single figures.

Getting a gun licence is a long and complicated process even for Japanese citizens, who must first get a recommendation from a shooting association and then undergo strict police checks.