An 11-year-old girl was stabbed multiple times by a boy who studies in Class XI at Prafulla Nagar in Belgharia, on the northern fringes of the city, on Wednesday afternoon, police said.

The girl, a student of Class IX in a school in Baranagar, was walking back home after school with her mother when the boy confronted them, a senior officer of the Barracpore Commissionerate said.

According to the officer, the girl and the boy had a brief argument after which the boy took out a knife and stabbed the girl multiple times.

The boy, a teenager, knew the route the girl and her mother took daily to reach home from school and was waiting inside a tunnel below Nivedita Setu, the police said.

“After the boy approached the mother and the daughter, the girl refused to speak to him. The boy the took out a knife and started stabbing her. When the girl’s mother tried to protect her the boy lunged at her as well,” the officer said.

Alerted by the woman and the girl’s screams, residents and passersby rushed to their rescue. They managed to stop the boy and snatch away his knife, the officer added.

The boy was then thrashed by the group. He had to be rescued by a team from the Barrackpore Commissionerate that reached the spot after being alerted by residents.

The girl and her mother were then taken to a nearby hospital. Later they were shifted to a private hospital off EM Bypass.

“The mother was discharged after treatment but the girl has been admitted and is scheduled to undergo surgery. She has been stabbed multiple times in the stomach and chest. Her hands too have stab wounds. She needed stitches,” said an official of the hospital.

Later, a group of residents of Prafulla Nagar blocked the Dakshineswar-bound flank of the Belgharia Expressway for around 30 minutes to protest against the incident.

Traffic heading out of the city through Jessore Road was affected and vehicles crawled on Jessore Road and the effect was felt on the airport-bound flank of the VIP Road as well.

An officer of the Bidhannagar Commissionerate’s traffic wing said that traffic on the airport-bound flank had slowed considerably on Wednesday afternoon.