Mitsubishi Fuso Truck and Bus Corp. offered free inspections on Thursday for all its 1.3 million vehicles on Japanese roads to allay drivers' worries after announcing a spate of recalls for serious defects, including wheels falling off and brake failures.

The Associated Press said the Japanese truckmaker, which is 65% owned by DaimlerChrysler, had previously said it needs to recall 450,000 trucks and buses. On Thursday, a company official reportedly said the number of recalled vehicles had climbed to more than 500,000 vehicles, although the precise figure was still being worked out.

The company will offer free inspections even to vehicles that are not being recalled, the automaker told AP. Fears are growing about the reliability of Mitsubishi vehicles, and any mishap involving Mitsubishi vehicles is being reported in Japan's media.

Another report said a Pajero (Shogun, Montero) SUV caught fire and burned to ashes on a mountain road last week while, earlier this week, a Fuso truck self-combusted.

The Associated Press noted that former and current Mitsubishi officials have been arrested on charges of professional negligence resulting in death in two 2002 accidents - in one accident, a wheel flew off a Mitsubishi truck and crushed a pedestrian to death while, in another, a truck driver died after his brakes failed and he crashed.

Japanese media reports on Thursday reportedly said that some of the arrested officials, including former Mitsubishi Motors Corp. President Katsuhiko Kawasoe, will be formally charged by prosecutors soon.

Tokyo-based Mitsubishi Motors, which has also announced recalls this year, spun off the truck unit last year, AP added.