Three people have been killed in a stabbing and shooting attack in central Japan, local media say.
A man in camouflage is said to have stabbed a woman and then used a hunting rifle in the city of Nakano, Nagano prefecture. Two policemen were also killed, and another person was injured.
The alleged attacker is holed up inside a building, Japanese media report.
Gun violence remains extremely rare in Japan, despite the killing of ex-prime minister Shinzo Abe in July last year.
According to Japanese news agency Kyodo, police received a call at around 16:25 (07:25 GMT) about a man who had chased and then stabbed a woman.
The man allegedly shot police officers who responded to the emergency.
He was said to have barricaded himself inside a building believed to be the residence of the Nakano city assembly speaker.
Abe was Japan's longest-serving prime minister and his death profoundly shocked a country where handguns are banned and incidents of political violence are almost unheard of.
In 2014, there were just six incidents of gun deaths in Japan, compared to 33,599 in the US.
People have to undergo a strict exam and mental health tests in order to buy a gun. Even then, only shotguns and air rifles are allowed.
