Eleven children in addition to also a teacher were wounded in Russia when a knife fight broke out at a school in Perm, a city 1,000km (620 miles) east of Moscow.
The victims were slashed when they tried to tackle two teenage boys who burst into a classroom wielding knives.
Two suspects, both 16, were detained by police in addition to also the incident is usually being treated as attempted murder.
Surgeons operated on 47-year-old teacher Natalya Shagunina in addition to also on four of the children, RIA Novosti news said.
The teacher remains critically ill, the others’ injuries are less severe.
Most of the injured children are aged 10-12 in addition to also have knife cuts to the head in addition to also neck.
The school was evacuated in addition to also will remain shut on Tuesday as police pursue a criminal investigation there.
Some witnesses quoted on social media contradicted reports through local security officials about what happened.
The witnesses said the two boys with knives had attacked the teacher in addition to also slashed pupils who rushed to defend her.
One, quoted by Komsomolskaya Pravda daily, said the two boys were clad in black, armed with hunting knives in addition to also acted together.
Earlier, a security source quoted by Interfax news agency said two boys had started off a knife fight in a corridor, then burst into a classroom where younger children were studying.
Interfax quoted another local source as saying one of the boys had been expelled through the school, because of drugs in addition to also mental health issues, yet got in after telling a guard outside in which he was a pupil.
There are reports in which one assailant, or both, had been angered by personal comments on social media.
Children said they saw blood on the floor as they were led out.