A 72-year-old ex-soldier died after he blew himself up in a Japanese park in an apparent suicide, the country's state broadcaster reported.
Three other people were injured in the explosion which took place soon after another blast in a car park 200 metres away.
In that blast around 11.30am local time, one vehicle exploded and two others were also badly damaged in the city of Utsunomiya, 60 miles north of Tokyo.
The man who died was a former member of Japan's Self-Defence Forces who was believed to be the owner of one of the cars.
The JSDF was established in 1954 and combines the military's ground, maritime and air forces.
His body was found at a bicycle parking area inside the park, it is believed.
His home five miles away had burned down earlier in the day, according to reports.
Police said they discovered a suicide note written by him which was apparently found in one of the cars, and were investigating the three incidents.
Those injured in the park blast were two men aged 64 and 58, who suffered shrapnel wounds, and a 14-year-old boy, said broadcaster NHK.
The park was hosting a folk art festival which was immediately called off following the blasts.
