Toyota secretly bought back from U.S. consumers vehicles it found with speed-control defects as part of a strategy to hide unintended-acceleration problems from safety regulators and the public, a revised lawsuit claims.

The repurchase transactions included strict confidentiality agreements barring consumers from disclosing the problem to anyone and from suing the automaker, according to the amended class-action complaint, Reuters reported.

The new complaint also cites internal company records documenting instances in which Toyota Motor Corp technicians or service managers replicated speed-control problems like those reported by customers.

And it says the company's confirmation of at least one clear-cut case of sudden unintended acceleration was concealed rather than reported to federal auto safety regulators.

The enlarged lawsuit, now more than 700 pages long plus hundreds of pages of attached exhibits, was filed on Wednesday in U.S. District Court in Santa Ana, California, south of Los Angeles.

It builds on a case consolidated over the summer from dozens of consumers and businesses claiming economic losses, including diminished vehicle resale values, stemming from complaints of Toyota cars and trucks racing out of control.

The thrust of the lawsuit is the contention that Toyota ignored evidence of speed-control problems in its vehicles for most of the past decade and failed to install a brake override system it knew could have prevented accidents.

Toyota acknowledged in a statement on Thursday that it has repurchased vehicles from customers who complained of unintended acceleration but did so to conduct "further engineering analysis" on the cars.

However, the company said its technicians have never been able to replicate those "acceleration concerns nor found any related issues or conditions in these vehicles."