TOKYO: A suspected gunman took at least two people hostage in a post office in Japan after wounding two other people in a shooting at a hospital, authorities and media said on Tuesday.

The government of the city of Warabi, just north of Tokyo, said in a statement an undetermined number of hostages were taken by a man "in possession of something like a handgun".

At least two female post office workers in their 20s and 30s were taken hostage, local media reported. A woman in her 20s later walked out of the building into police custody, national broadcaster NHK said.

The suspect, who appeared to be in his 80s according to NHK, was earlier involved in a shooting at a hospital in the neighbouring city of Toda and then fled the scene, municipal authorities there said. Two people were injured at the hospital, media reported.

Images broadcast on television showed a man wearing a track suit top and white shirt standing just inside the post office brandishing what looked like a pistol. Several police officers wearing body armour were stationed nearby.

Violent crime, especially incidents involving guns, is rare in Japan.

There were just nine shooting incidents last year, according to the national police agency, of which six were related to criminal gangs.

Those incidents resulted in four fatalities, including the killing of former Prime Minister Shinzo Abe by a man with a homemade gun at a campaign rally in July.