Denison Police said no one was injured Monday after a Denison Independent School District bus caught fire on U.S. Highway 75.

Lt. Paul Neumann said no children were on board the bus when flames broke out in the engine compartment, forcing the driver to pull over near the intersection with U.S. Route 69.

“The driver had taken it out for a test drive and heard a pop in the engine just before it caught on fire,” Neumann said.

The Denison Police lieutenant said the driver was able to escape the vehicle before the flames began to spread. Neumann said Denison Police and Denison Fire Rescue crews shut down Highway 75 while firefighters extinguished the flames.

A message left with Denison Fire-Rescue was not immediately returned Monday. It was unclear whether investigators had determined a cause for the fire.

A Denison ISD spokesperson said the district was aware of the incident, but was not prepared to offer a statement Monday. Students were not in class Monday as the district observed Presidents Day.

Neumann said the fire remains under investigation.