Cape Town - A Grade Five classroom and a library were torched at Marconi Beam Primary school in Milnerton on Monday.
Police spokesperson Noloyiso Rwexana said the police are investigating a case of arson.
Rwexana said there were no arrests so far.
Western Cape Education Department (WCED) spokesperson Bronagh Hammond said people gained entry onto the premises and allegedly set alight the school building.
Hammond said the motive was not clear. "They torched the library and a Grade 5 mobile classroom."
She said pupils and educators were sent home for safety reasons on Tuesday.
"This is a callous and dangerous act. It is absolutely appalling and is condemned," Hammond said.
She said the school usually houses 1 700 pupils. "While not all these pupils are back due to the phased in approach of schools, the effects on the pupils of this school are already negative. They have already lost a day’s schooling, and have lost their school library."
She said the full extent of the damages was being assessed as well as the costs involved. "The areas affected now need to be cordoned off so that pupils can return safely."