MANILA, Philippines -- Classes at Rizal Technological University were suspended at 8 p.m. Friday after a fire broke out at a residential area behind the school in Mandaluyong’s Barangka Ibaba district.

School security guard Peter Cabalquinto said no one was injured as the school was evacuated.

Mandaluyong fire marshal Chief Supt. Benjamin Ladra said the fire broke out at around 7:15 and gutted 10 houses before it was put under control 35 minutes later.

He said the cause of the fire was still being investigated.

But Gina Inigo, a housewife, whose house was burned to the ground, said the fire may have been caused by what seemed to be homemade incendiary bombs thrown by unidentified people onto the roof of her house on Irid Street.

“I heard bottles being thrown on my roof followed by explosions and then fire,” she told the Philippine Daily Inquirer (parent company of INQUIRER.net). She said she counted at least three bottles popping.

Ladra said at least 40 people were displaced by the fire, but no one in the neighborhood was reported injured by the fire, which snarled traffic on nearby Boni Avenue.