Former Japanese Prime Minister Shinzo Abe died on Friday after being shot at a political campaign event in Nara city, the country’s public broadcaster NHK reported.

Abe, 67, was Japan’s longest-serving prime minister and one of its most powerful figures.

Doctors at the Nara Medical University said that Abe sustained two bullet wounds on his neck and his heart. He bled to death and there was “a wide gaping hole in the heart” from the gunshot wound, the doctors said, according to the Voice of America.

Videos of the event on social media showed Abe giving a speech and then a plume of smoke forming behind him as he collapsed. He was flown to hospital by helicopter after the attack. A fire department official told CNN that Abe was in a state of cardiopulmonary arrest, a term used to describe the sudden loss of heart function and breathing.

At a news briefing before Abe’s death was announced, Japanese Prime Minister Fumio Kishida said the attack on Abe was a “heinous act”.

Kishida appeared close to tears and said, “This attack is an act of brutality that happened during the elections – the very foundation of our democracy – and is absolutely unforgivable.”

The police arrested the suspected gunman from the scene of the attack. He was identified as 41-year-old Yamagami Tetsuya, reported NHK. They seized a weapon from him, which was reportedly a handmade gun.

Many more handmade weapons, like the one used for the assassination, were confiscated form the assailant’s home, BBC reported, citing the police. Explosives were also found at the home.

Tetsuya admitted to shooting Abe and said that he had a grudge against a “specifice organisation”, police said, according to BBC.

Abe was shot while he was delivering a campaign speech in support of a member of the Liberal Democratic Party from Nara, who was running for re-election in the Upper House of Japanese Parliament.

The assailant fired at the former prime minister twice. A witness told NHK that she did not see anyone fall down after the first shot but Abe collapsed when the second shot was fired.

The witness also said that suspect did not try to flee and was caught by security personnel.

Gun violence is very rare in Japan as licence for firearms are very difficult for citizens to obtain in the country. Annual deaths from firearms in Japan are regularly reported in single figures.

Modi says he is ‘saddened beyond words’

Prime Minister Narendra Modi wrote on Twitter that he was “shocked and saddened beyond words” at Abe’s death

“He was a towering global statesman, an outstanding leader, and a remarkable administrator,” Modi wrote. “He dedicated his life to make Japan and the world a better place.”

In India, a one day of state mourning has been declared for Saturday and flags will be flown at half-mast.

Other leaders of the international community also expressed concern about Abe.

“Utterly appalled and saddened to hear about the despicable attack on Shinzo Abe,” British Prime Minister Boris Johnson tweeted. “My thoughts are with his family and loved ones.”

New Zealand Prime Minister Jacinda Ardern said she was deeply shocked to hear the news about Abe.

“He was deeply committed to his role, and also generous and kind,” Ardern said. “I recall him asking after the recent loss of our pet when I met him, a small gesture but one that speaks to the kind of person he is. My thoughts are with his wife and the people of Japan. Events like this shake us all to the core.”