By CHANG-RAN KIM

TOKYO — A schoolgirl and an adult man were killed and 16 other young girls injured in a stabbing at a bus stop outside Tokyo on Tuesday, Japanese national broadcaster NHK cited authorities as saying, and another man detained at the scene also later died.

The girls, aged between 6 and 12, were students at a private Catholic school in Kawasaki city, south of Tokyo, and were boarding their school bus when the suspect attacked them, according to NHK.

The driver of the Caritas Elementary School bus told police he saw a man approach the bus stop and start slashing at people, holding a knife in both hands, the broadcaster said.

Police said an 11-year-old girl and a 39-year-old man were killed. NHK said the man was likely the father of one of the children, while another woman was severely injured along with the 16 other schoolgirls who were hurt.

A suspect was detained at the scene after stabbing himself in the neck but died later, NHK cited police as saying. It said the man, a Kawasaki resident probably in his 50s, was unconscious when he was detained.

The motive for the attack was not yet clear but there were no immediate fears of a wider security threat. There have been previous examples of mass stabbings in Japan, sometimes involving the vulnerable.

In an apparently unrelated incident, a police officer shot a man who approached him with a knife in his hand in a town north of Tokyo, Kyodo news agency reported. The man was taken to hospital but no other details were available.

The attack occurred on the final day of U.S. President Donald Trump's four-day state visit to Japan.

"On behalf of the First Lady and myself, I want to take a moment to send our prayers and sympathy to the victims of the stabbing attack this morning," Trump said as he toured Japan's largest warship, the Kaga.

"All Americans stand with the people of Japan and grieve for the victims and for their families," he said.

TV footage showed scores of police officers and emergency vehicles at the crime scene, with large areas cordoned off.

A witness told NHK he saw people lying on the ground covered in blood and one police officer was seen hosing down the sidewalk.

"I saw a boy carrying a school bag with scratches on his face, wrist and legs in a parking lot," NHK quoted an unidentified witness as saying.

"He was visibly trembling - frightened and shocked."

The girls' school is located just over a kilometer from the scene of the attack, NHK said.

Japanese Prime Minister Shinzo Abe described the attack as "extremely harrowing" and promised to step up efforts to secure the safety of children commuting to and from school.

Two children were killed and a dozen injured in western Japan earlier this month after a car involved in an accident with another vehicle skidded into a nursery school group out for a walk with their teachers.

Violent crime is relatively rare in Japan but occasional high-profile incidents have shocked the nation.

A knife-wielding man broke into a facility for the disabled in a small town near Tokyo in 2016 and killed 19 patients in their sleep. In 2001, eight children were stabbed to death by a former janitor at their school in Osaka.

More than a dozen people were injured in a 2010 stabbing spree on a school bus and a commuter bus in a Tokyo suburb. — Reuters