In a significant shift, federal safety regulators on Tuesday called on automakers to conduct a nationwide recall of vehicles that contain driver’s-side airbags made by the Japanese supplier Takata.

The nationwide move, urged by the National Highway Traffic Safety Administration, would expand a recall that has been mostly limited to two states and two territories associated with high humidity. If automakers do not agree to expand the recall, the agency said, it will “use the full extent of its statutory powers” to compel automakers to do so. The call, though, was likely to create confusion among car owners.

The agency said it had yet to make a detailed list of the models or model years affected. But the expansions will affect millions of vehicles made by Ford, Honda, Chrysler, Mazda and BMW, mostly from model years 2008 or earlier, said David J. Friedman, the agency’s deputy administrator, on a conference call with reporters.

The announcement reflects a growing urgency within the agency to address the mushrooming problem of the Takata-made airbags. Last month, it urged millions of car owners to have their vehicles fixed immediately, only for many to learn that replacement parts were not yet available. Tuesday’s announcement also came two days before Mr. Friedman was expected to testify about his agency’s handling of the Takata issue at a hearing of the Senate Committee on Commerce, Science and Transportation. Representatives of Takata, Honda and Chrysler are also set to appear.