BOSTON (CNN) – A device planted next to a Boston police car caused the vehicle to catch fire on Friday morning in what appears to be a “deliberate” attempt “to blow up one of our cruisers,” law enforcement officials said.

A police spokesperson said the device was wedged between the cruiser and a bridge on West Broadway in South Boston, near a Boston police station. Boston Police Commissioner William Evans said the device appeared to be a propane tank.

When an officer got into the cruiser and began driving, the tank exploded, Evans said.

“Luckily, nobody was hurt,” Evans said. “Clearly, we’re looking at this as a deliberate act.”

No arrests have been made. The FBI, bomb squad, and arson squad are at the scene investigating, according to a police spokesperson.