TOKYO (AFP, REUTERS) - One person was killed and three others injured by two near-simultaneous blasts in a Japanese park on Sunday (Oct 23), the local fire department said.

The explosions occurred at a park in Utsunomiya, some 100km north of Tokyo, shortly after 11.30am local time (10.30am Singapore time), a fire department spokesman said.

According to Reuters, public broadcaster NHK later reported that a 72-year-old retired soldier had blown himself up in an apparent suicide. He was killed in the first blast while three other people were injured in a second, separate explosion which also caused a fire in a carpark, The man's home, which was about 8km from the park, also burned down.

Police in the city said they discovered a suicide note and were investigating the three incidents, but gave no further details.

NHK added that two men, 64 and 58, suffered severe injuries. TV Asahi said they sustained shrapnel wounds, following the explosion inside the park. A 14-year-old boy was also injured in the incident.

NHK footage showed a car completely charred, as fire fighters poured water on it. A man told NHK that he "smelled gunpowder in the area" after the explosions.

The Yomiuri Shimbun daily said one of the parked cars exploded and burnt down two other vehicles there.

Minutes later police found a scorched, dismembered man's body inside the park, it said.

A folk art festival was taking place there but was immediately called off following the blasts, it said.

Explosions of this kind are rare in Japan, although small pipe bombs blasts linked to extreme leftists occasionally hit near US military bases.

In November last year, a homemade pipe bomb exploded at a controversial Tokyo war shrine, damaging the toilets at the facility but no one was hurt.

A South Korean man was later arrested and sentenced to four years in prison after admitting to detonating the bomb at the Yasukuni Shrine, which has been targeted by activists who see it as a symbol of Japan's militaristic past.