The inspections at Toyota’s offices in central Japan would continue over the next few days, Japan’s Ministry of Transport told CNN. It comes as the world’s biggest carmaker by sales grapples with growing concerns over the certification of some of its vehicles.

The ministry said five automakers — Toyota (TM), Mazda, Honda (HMC), Suzuki and Yamaha — had submitted incorrect or manipulated safety test data when they applied for certification of the vehicles.

Toyota, Mazda and Yamaha were ordered to suspend shipments of some vehicle models, including the Corolla Fielder and Corolla Axio. All five companies were told to review their safety certification processes.

A probe already undertaken by Toyota had revealed that at least seven of its models, some of them discontinued, were tested using methods that differed from government standards, the company said Monday in a statement.