A U.S. safety regulator ordered Takata to preserve all air bag inflators removed from vehicles during a recall process as evidence for a federal investigation and private litigation cases.

The order marks the first time that the National Highway Traffic Safety Administration has ordered any company to preserve evidence for private litigation, Gordon Trowbridge, a spokesman for NHTSA, said to Reuters.

The faulty parts, which activate air bags in the event of a collision, have been linked to six deaths and dozens of injuries so far and resulted in a number of lawsuits. The safety administration believes the air bags are exploding with too much force, thus spraying metal fragments at occupants.

NHTSA announced last Friday that it will fine Takata $14,000-per-day for failing to fully cooperate with the government's probe. Since 2008, 25 million vehicles worldwide with Takata air bags have been called back.

U.S. Secretary of Transportation Anthony Foxx is also prohibiting Takata from damaging or destroying any air bag inflators except those needed for testing, according to Reuters.

Takata must set aside 10 percent of recalled air bag inflators and make them available for testing by private plaintiffs. NHTSA mainly wants to make sure all parties testing the inflators could have access to them, from the safety administration itself to a number of different automakers.

A spokesman for the Japan-based safety company, Bob Rendine, said the company will continue to work closely with NHTSA.

"We believe the outcome (Foxx's order) is in the best interest of all parties, and consistent with our commitment to the safety of the driving public. Determining the root cause of the inflator issues has been, and remains, our top priority," said Rendine to Reuters.

NHTSA will upgrade its Takata investigation to an engineering analysis, a formal step in the safety agency's defect investigation process.

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