Two people have been injured in a shooting at a hospital in the central Japanese city of Toda, local media report.
The suspect, possibly in his 40s or 50s, fled on a motorcycle and is currently at large.
Meanwhile, at least one person has been taken hostage inside a post office in neighbouring Warabi, the city said.
It is as yet unclear if the two incidents are connected.
Japanese media has aired footage of a man carrying a gun and standing at the entrance of a post office near the Toda Chuo General Hospital where the two people were shot.
The two injured people have been identified as an doctor and an elderly patient.
The post office mentioned by Warabi authorities is about 2.5 km (1.5 mi) from the Toda Chuo General Hospital.
Footage also showed police and ambulances surrounding the area.
Police said someone reported a gun being fired in the hospital at around 13:00 local time (06:00 GMT).
The hostage situation in Warabi was reported around 14:15.
Tokyo police have dispatched officers from a special investigations team that handles hostage situations to the scene, according to Japanese broadcaster NHK.
Authorities also asked people living within a 300m radius of the Warabi post office to leave the area, according to local media.
Buildings nearby have also been placed on lockdown.
Shootings are rare in Japan. The country has strict gun ownership rules, and only allows civilians to own hunting rifles and airguns.
Owners must undergo a strict exam and mental health tests.
