TOKYO — A Japanese man carrying two knives waded into a crowd of schoolgirls at a bus stop outside Tokyo on Tuesday and began stabbing them one by one, killing an 11-year-old and an adult and wounding at least 17 others.

The middle-aged man then apparently committed suicide by stabbing himself in the neck, state broadcaster NHK reported, citing police. 

The children, between the ages of 6 and 12, are students at a private Catholic school and were lining up to board their school bus when the man attacked about 7:45 a.m. in Kawasaki city, Japanese media reported.

NHK reported that the adult who was killed was a Japanese Foreign Ministry official, Satoshi Oyama, 39, whose daughter attends the school. The broadcaster said 16 children and an adult were wounded.

Hospitals confirmed the additional death of a man in his 50s, thought to be the attacker. Three girls and a woman in her 40s were seriously injured.

“I heard children scream, ‘I’m scared,’ and then turned to see a man with knives shouting, ‘I’m going to kill you,’ ” Toshichika Ishii, 57, who was at a park near the site, told Kyodo News. He said he saw children falling to the ground.

But Satoru Shitori, the deputy principal of the Caritas Elementary School,  disputed this account, saying the man assaulted the children from the back of the line without saying a word. “And that’s why the children didn’t notice,” Shitori said. “They were looking toward the bus.”

Police quoted a bus driver who witnessed the assault as saying, “I tried to stop him, but he started stabbing children and others,” Kyodo reported.

“He then moved dozens of meters away and stabbed his own neck,” the driver said, according to police.

Discarded backpacks were scattered amid pools of blood, local media outlets reported, and the two knives were found nearby.

One witness described to NHK being haunted by the children’s screams. Another recalled hearing them crying by the roadside, one calling, “Mom, Mom.”

In an emotional news conference, officials from the school expressed shock about the attack, saying that most of the victims were first-graders. 

The 11-year-old girl who died would always smile and say good morning enthusiastically every day, said Sadako Naito, the principal. 

“I can’t believe it,” she said, choking with emotion as she spoke. “I thought I would hear her cheerful voice again.”

Prime Minister Shinzo Abe described the attack as “extremely harrowing” and promised to increase efforts to secure the safety of children commuting to and from school. “I feel strongly indignant that young children fell victim to this,” he said.

The attack happened as President Trump was in Japan on a four-day state visit.

“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 in Tokyo,” Trump said in a speech aboard a Japanese aircraft carrier. “All Americans stand with the people of Japan and grieve for the victims and for their families.”

Violent crime is rare in Japan, and gun ownership laws are strict, but there are occasional high-profile attacks, often involving knives or vehicles .

Earlier this month, a man left two knives on the school desk of a young Japanese prince. Police said the man confessed that he had intended to stab 12-year-old Prince Hisahito because he disagreed with the imperial system. The prince one day stands to inherit the Chrysanthemum Throne as Japan’s emperor.

Another man drove a minivan into a group of people during New Year’s celebrations in Tokyo just after midnight on Jan. 1, injuring eight people in an attack he said was to protest the death penalty.

In 2016, a man who claimed he wanted to kill disabled people carried out a knife attack on a care facility where he had worked, killing 19 and wounding 26 more.

In 2010, 13 people were injured when a man who said he wanted to end his life went on a stabbing rampage on a school bus and a commuter bus in a Tokyo suburb.

Two years earlier, a 28-year-old man drove a truck into a crowded pedestrian crossing in Tokyo, killing three people, and then descended from the vehicle to fatally stab four more.