A controversial state funeral in Japan for the assassinated former Prime Minister, Shinzo Abe, has begun in the capital Tokyo.

Under massive security precautions, around 4,300 mourners from home and abroad gathered in the capital on Tuesday for the rare state ceremony.

Accompanied by cannon shots, Abe’s widow Akie, dressed in a black kimono, entering the Nippon Budokan hall with her husband’s urn.

Mourners took their seats in the hall in front of a large portrait of the assassinated ex-premier.

In a nearby park, people had been laying flowers and praying at two tables laid out for the occasion since the morning.

However, the state act of mourning also triggered angry protests.

In polls, a majority said they rejected the state ceremony for Abe, and said that current Prime Minister Fumio Kishida who also belongs to Abe’s conservative party had no right to give Abe such a state honour.

Kishida had argued that Abe deserves a state funeral given to him as he was the country’s longest-serving premier.

Some 20,000 police officers have been deployed for the event in case of any unrest.

The conservative leader was shot by a former military officer with a home-made gun during a campaign speech in the city of Nara on July 8.

His assassin has said since his arrest that he did not kill Abe on account of his political convictions, but rather out of hatred for the controversial Unification Church of Korean religious leader Sun Myung Moon, to which he linked Abe.

He told investigators that his mother had donated money to the church and in so doing ruined the family financially.