A man carrying a knife in each hand has stabbed to death a 12-year-old girl and a man before killing himself, according to reports, in an attack near Japan's capital that also left more than a dozen people, including several children, wounded.

Most of the victims in the attack on Tuesday morning were schoolgirls who were lined up at a bus stop near Noborito Park in the city of Kawasaki, just south of Tokyo, when a man reportedly in his 50s began slashing them with knives.

National broadcaster NHK quoted police as saying that that the suspect died after cutting himself in the neck. Police did not immediately confirm the specifics of that report. The attacker's identity and motive were not immediately known.

Kiyoshi Matsuda, deputy director of the Nippon Medical School Musashi Kosugi Hospital, told reporters that the 12-year-old schoolgirl and a 39-year-old man had succumbed to their wounds.

The Kawasaki City fire department put the number of wounded at 19, including three with severe injuries.

Al Jazeera's Wayne Hay, reporting from the scene, said the attack took place near a train station and a bus stop at a time when the area was likely to be very busy with commuters.

"Children [at the bus stop] were waiting to go to school. It seems that that is where most of the people were attacked - most of them, it seems, were schoolchildren waiting to get on a bus to go to a private Catholic school in the area," Hay said.

"We are told that at that time of the day, the children lining up for that particular bus were for the most part Grade One students - children between six and seven years old," he added.

Japanese Prime Minister Shinzo Abe voiced "strong anger" over the attack.

"It is a very harrowing case," Abe said in a televised statement. "I offer my heartfelt condolences to the victims and hope the injured recover quickly."

Footage broadcast on local TV stations showed multiple police cars, ambulances and fire engines at the scene.

Emergency medical tents were put up to treat the wounded.

A witness told the Mainichi newspaper that he heard children shrieking after walking past a bus. He said that when he turned around, he saw a man wielding a knife in each hand, screaming "I will kill you!" and several children were on the ground.

NHK, citing police, said that a bus driver told officials that a man holding a knife in each hand walked towards the bus and started slashing children. NHK also interviewed a witness who said he saw the suspect trying to force his way onto a bus.

"I heard screaming, then I saw a man standing with a knife in each hand," NHK quoted an unidentified witness as saying. "Then he crumbled to the ground."

Two knives were found at the scene, NHK said. (Al Jazera and News Agencies)

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