Japanese police detained a reportedly 86-year-old man  who held several people hostage in a post office after apparently shooting into a hospital and injuring two people on Tuesday.

After a standoff lasting eight hours in Warabi, outside Tokyo, police said they finally detained the man after 10 pm (1300 GMT) after surrounding the three-storey building.

"The man has been detained. Details will come later," a spokesman for Saitama Prefecture Police outside Tokyo told AFP. 

Authorities confirmed he had been taken into custody but gave no further information. 

Broadcaster NHK named him as Tsuneo Suzuki, 86.

The Asahi Shimbun daily reported that police stormed the building, took the man into custody and confiscated his gun.

His motive was not immediately clear.

Police believe he was the same man who earlier in the day had wounded two people in a nearby hospital before escaping on a motorbike. 

Media reports said that a suspicious fire in an apartment block may also be linked.

He had holed himself up in the post office at around 2:15 pm (0515 GMT) in possession of "what appears to be a gun," the city authorities had said.

Later, as police negotiated with the man, television footage showed a woman in her 20s, believed to have been a hostage, walking out of the post office shortly before 7:30 pm. 

"This is a quiet neighbourhood. I can't believe something like this is happening," resident Tetsuo Sasaki, 70, told AFP.

"I used that post office just yesterday," said his wife Reiko Sasaki, 64. "I could have been at the wrong place at the wrong time. I could have been the target."

Hospital shooting

Two people were slightly wounded — reportedly a doctor and a patient — after shots were apparently fired from the street into the hospital in Toda.

Police "believe the man was at the hospital and came to the post office", a city official told AFP.

"After 1:00 pm, I heard a woman shouting 'Someone, please come,' and a nurse told me, 'Stay away from the windows and keep your head low,'" a man in his 60s who was inside the hospital told broadcaster NHK.

"Around 2:00 pm, I looked inside the doctor's office, and saw a pool of blood next to an examination table. I didn't hear a gunshot. But a nurse said she heard two gunshots," the man said.

Fuji TV said police were also investigating a possible link between the man and a fire at an apartment building in Toda earlier in the day. No one was injured in the blaze, it said.

Violent crime is rare in Japan, in part because of strict regulations on gun ownership, but cases still occur.

Last year, former  prime minister Shinzo Abe was shot dead and this April a man hurled an explosive towards current Prime Minister Fumio Kishida. Kishida was unharmed.

The following month, a man holed up in a building after allegedly killing four people, including two police officers and an elderly woman, in a gun and knife attack.