PORTLAND — A school bus sustained extensive damage after it caught fire in the parking lot off Allen Avenue, the district said in a press release Thursday afternoon.

The bus was being repaired in the district’s transportation center on the Portland Arts and Technology High School campus when it caught fire shortly after 10 a.m., the district said.

A school employee was patching up damaged bus seats using tape, liquid vinyl and a heat gun when the fire began.

No one was injured in the fire, which was extinguished by the Portland Fire Department. The 5-year-old bus sustained “extensive damage,” the district said.

District officials said preliminary estimates indicate the bus sustained about $35,000 in damage.