As a result of a shooting and stabbing in Japan, three people were killed, one was injured, and the suspect was barricaded in the building, local media reports.
A woman fell while being chased by a masked man, who then stabbed her and fired an assault rifle at two police officers who arrived at the scene in Nakano, Nagano Prefecture, a witness told public broadcaster NHK.
The three were taken to a nearby hospital, where the woman was pronounced dead, police said.
The two policemen also died later, NHK reports.
The fourth person who was injured could not be saved because he was lying near the place of the attack, Kyodo News agency reports.
The suspect is believed to have barricaded himself in the house of the city council president, and several gunshots were heard near the scene, the news agency added.
NHK footage showed uniformed police wearing body armor and carrying shields near the ambulance.
The city authorities called on those in the area to stay at home.
Police described the suspect as a man wearing camouflage gear, a hat, a mask and sunglasses, Kyodo News reported.
No other details about the suspect and his motives are known.
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Gun-related crimes are rare in Japan, where gun ownership is strictly regulated and anyone who wants to own a gun must go through a rigorous process to obtain a license.