The FBI raided the U.S. offices of three auto suppliers to Toyota and other manufacturers as part of an antitrust investigation, the agency told The Associated Press.

The FBI's Detroit office said agents raided the offices of Denso Corp, Yazaki North America and Tokai Rika. All the raids took place Tuesday evening. There was no immediate indication the investigation involved the safety of the auto parts.

Justice Department spokeswoman Gina Talamona said the department is conducting an investigation of automotive electronics suppliers. It was unclear if other companies were involved in the investigation.

"The antitrust division is investigating the possibility of anticompetitive cartel conduct," Talamona said in a statement. "We are coordinating with the European Commission and other foreign competition authorities."

Denso spokeswoman Julie Kerr says the search of the company's office — which oversees Denso's operations in North and South America and is located in Southfield, Mich. — took place on Tuesday. She declined to offer details of the investigation but said it is unrelated to Toyota's recent recalls.

Yazaki spokeswoman Shefali Cromer said FBI agents searched its U.S. headquarters in Canton, Mich., as well as offices in Lexington, Ky., and Columbus, Ohio. Cromer, whose company makes electronics for several automakers, said the officials reviewed documents, but she was unaware of the nature of the investigation.

Tokai Rika spokesman Joe Rine also confirmed a raid and said the company would be cooperating.

"We haven't done anything wrong. We'll supply them with all the information," said Joe Rine, a local spokesman for Tokia Rika, which makes interior components for Toyota, Ford Motor Co., General Motors Co. and Nissan Motor Co.

A person familiar with the antitrust investigation said it involves possible discussions among the parts suppliers, not the safety of the parts themselves. This person spoke to the AP on condition of anonymity to be able to speak more fully about the matter.

Toyota is Denso's biggest customer and is one of two suppliers of its gas pedals. While gas pedals from the other supplier, CTS Corp., were involved in Toyota's sticky-accelerator recall, Denso's have not been implicated.

Toyota said in a statement that it was aware of the raids but has little information about the investigation. Toyota said it has not been contacted by authorities.