U.S. auto safety regulators on Thursday ordered Japanese supplier Takata Corp. to provide documents and answer questions under oath related to the government's ongoing probe of potentially defective Takata air bags in millions of U.S. vehicles.

The National Highway Traffic Safety Administration sent a special order to the supplier's American unit, TK Holdings Inc., ordering delivery of the documents by Dec. 1.

Takata spokesman Alby Berman said on Thursday the company "is cooperating fully with NHTSA and is working to meet their requests."