MOSCOW (Reuters) - A Russian teenager attacked a group of younger students with an ax, injuring six people, before setting his school on fire, investigators said on Friday.

Russia's Investigative Committee said the attacker, a ninth-grader, attacked a group of seventh-grade students with an ax at a school just outside the Siberian city of Ulan-Ude, then set the room ablaze.

Five students and one teacher were injured in the attack, the committee said. The attacker was detained and was now hospitalized after a suicide attempt, the committee said.

Earlier this week, investigators opened a criminal case into a knife attack that injured 15 people at a school in the city of Perm. The case was initially reported as an assault by two masked men, but authorities later said it grew out of a knife fight between two students.

(Reporting by Gabrielle Tétrault-Farber, editing by Larry King)