TOKYO (AP) _ Tokyo prosecutors on Wednesday raided three major Japanese textile makers over suspected bid-rigging in the U.S. market for carbon fibers.

Officials of the companies involved _ Toray Industries Inc., Toho Rayon Co. and Mitsubishi Rayon Co. _ confirmed that their headquarters in Tokyo were searched, but refused to discuss details.

Kyodo News agency said the raids were conducted at the request of U.S. authorities over an alleged cartel among the three companies, which produce a combined 70 percent of the world's carbon fibers annually.

Prosecutors will send related materials, including production and sales data collected from Wednesday's raids, to the FBI, said national broadcaster NHK.

Toray said that its U.S. subsidiaries and related firms have been under investigation by the U.S. Justice Department since January of last year.

``Our company is convinced that there is no truth to the allegations,'' Toray said in a statement.

In a separate statement, Mitsubishi Rayon said it will fully cooperate with the prosecutor's investigation. Spokesmen for Toho Rayon and the Tokyo District Public Prosecutors Office both declined to comment.

Carbon fiber is lighter and stronger than metal fiber, and is used in sporting goods, including golf clubs and tennis rackets, and structural material for large passenger jets.