MOSCOW -- At least 15 people were injured during a knife attack at a school in the Ural mountains city of Perm, Russian authorities said Monday. The local Investigative Committee said teachers and other students were injured when they tried to break up a fight between two students.

A female teacher and two students around 15 years old were seriously wounded and required surgery, the regional health ministry said. Nine children received what the department calls "superficial injuries."

Of the 15 who were hurt, 12 were hospitalized, the city health department said. Investigators said they are treating the incident as attempted murder of two or more people.

Get Breaking News Delivered to Your Inbox

Investigators said the two suspects have been detained, the Reuters news agency reports. Nearly 700 students attend the school.

According to Reuters, media reports initially stated that two masked men burst into the school and attacked students, but authorities later said the began as a fight between the two students.