Japan's transport ministry has raided the headquarters of car maker Suzuki.

The move on Friday is in the wake of its shock admission that it used improper fuel-testing methods for years. Officials descended on the company's base in Hamamatsu city, saying they were hunting for documents linked to the unapproved testing methods.

The agency also raided the office of its rival Mitsubishi Motors, after the revelation in April that it had cheated on fuel-efficiency tests for decades as well.