The headquarters of Suzuki Motor Corp were raided by Japanese authorities on Friday in an effort to investigate improper fuel economy tests that were being conducted by the automaker.

Transport ministry officials indicated that they were seeking evidence to substantiate claims by Suzuki that the company had performed tests on individual parts rather than through vehicle coasting tests.

The improper testing affects 14 models branded under the Suzuki name and 12 models that are sold under other marques.

Suzuki maintains that a lack of resources and increased development demands are behind its inability to comply with regulatory testing standards.