DETROIT — U.S. safety regulators are investigating a fuel tank problem that could affect more than 2.7 million Ford F-150 pickup trucks.

The National Highway Traffic Safety Administration said today that the steel straps holding up the truck’s gas tank can rust and break, possibly causing a fuel spill and fire. No injuries have been reported from the possible defect.

The agency is looking into trucks from the 1997 through 2001 model years. NHTSA’s investigations often lead to recalls.

NHTSA began looking at the fuel tank problem last year after it received 32 complaints. NHTSA and Ford have now received 243 reports of the tanks falling. In two incidents, a fire started when the fuel tank fell. One of the fires destroyed the pickup, while the other extinguished itself.