A fire burned part of an elementary school in a densely populated area of Tokyo on Friday, leaving 10 people, mainly children, injured.

The fire started around 11 a.m at Takinogawa Daisan Elementary School in Kita Ward. It was mostly extinguished in about an hour after burning across an area of about 200 square meters.

According to sources including the Tokyo Fire Department, the fire likely started in a music room on the fourth floor.

Firefighters rescued three pupils and one teacher who could not escape.

One pupil suffered a bone fracture while evacuating, and seven others had smoke inhalation or other injuries. Two teachers were also injured.

The sources said that all of the 10 people sent to hospital were conscious.

Tokyo¡¯s Metropolitan Police Department and the fire department are investigating the cause of the fire.

According to the police, a class for fifth graders was being held in the music room when the fire began. A burning smell was coming from a room used to store musical instruments.

The school, located about 500 meters south of Oji Station, has about 340 students.