A school bus with high school students on board caught fire Tuesday morning in Southern Maryland, but no one was injured, authorities said.

The incident happened just before 8 a.m. near Point Lookout and Fairgrounds roads, according to the St. Mary’s County Sheriff’s Office. The bus was full of students headed to Leonardtown High School when “the engine compartment began to smoke,” officials said.

The bus driver pulled over to the road’s shoulder in front of a nearby middle school and evacuated the students off the bus. The vehicle caught fire when all the students were safely off the bus, the sheriff’s office said in a statement.

Some roads in the area were closed as investigators were on the scene. The cause of the fire is under investigation.