DETROIT -- General Motors said Friday that it was expanding its ignition-switch recall to include an additional 971,000 small cars worldwide, including 824,000 in the United States, that previously may have been repaired with defective switches.
GM was already recalling 1.6 million older-model vehicles worldwide to replace switches that could accidentally be jostled and cut off engine power, deactivating air bags.
On Friday, the company said it would now also recall Chevrolet Cobalts and other cars from the 2008 model year and afterward.
The initial recall was for Cobalts and other small cars made in the 2007 model year and before.
The expanded recall was announced as lawmakers increasingly voiced concerns over the safety of the recalled cars.
On Friday, before GM's announcement, Rep. Diana DeGette, D-Colo., called for owners of those cars to stop driving them until they could be fixed, which may take months.
Ms. DeGette called the ignition problem "terrifying," adding, "I think people should stop driving them until they can get fixed."
General Motors has said it has evidence of 12 deaths tied to the switch, which can turn off if it is bumped, shutting off the engine and disabling the air bags. But the number may be far higher, Ms. DeGette said, because that counts deaths only in cases where the air bag failed to deploy. If the engine shuts down, she said, some people may have died even if the air bag worked.
Her comments followed a letter sent this week by Sen. Richard Blumenthal of Connecticut urging GM's chief executive, Mary T. Barra, to warn owners not to drive the recalled cars.
"I urge you to issue a stronger warning to drivers of recalled vehicles of the acknowledged risk they are facing, including a warning not to drive recalled cars," he wrote.
Their statements are a hint of what Ms. Barra can expect to face next week when she testifies, along with David Friedman, the nation's top auto safety regulator, before committees in the House and Senate. Ms. DeGette is the ranking minority member of the Energy and Commerce subcommittee, which will hold a hearing Tuesday. The Senate hearing is Wednesday.
GM and Ms. Barra have insisted that the car is safe if the driver removes everything except the key from the key chain.
But GM told its dealers in a service bulletin after the recalls that customers who asked for a loaner car until their recalled car is fixed could get one.
"Dealership service management is empowered to place the customer into a rental or loaner vehicle until the parts are available to repair the customer's vehicle," the company told dealers.
Ms. DeGette, though, said many consumers were not aware of that offer and that GM had not done enough to publicize it. It is on the National Highway Traffic Safety Administration's website as one of 13 documents attached to the recall notice, rather than being in the notice itself, which was mailed to car owners.
"It's like a secret loaner car," she said.
The ignition switch recall has forced GM to re-examine its safety efforts and recall procedures, and to pay closer attention to quality issues in its current models.
That effort may have played a part in the company's decision Friday to stop selling 2013 and 2014 Chevrolet Cruze compact cars that had already been delivered to dealers.
GM confirmed that it told dealers not to sell Cruzes equipped with 1.4-liter turbo gasoline engines, which the company said represented about a third of the car's overall inventory.
A company spokesman, Greg Martin, declined to say whether the Cruze had a safety problem or some other type of mechanical or quality issue. There was no indication when sales would resume.
It is rare for an automaker to stop sales of a car unless there is a safety problem. Two years ago, Ford Motor stopped selling its revamped Explorer because of a possible fuel leak. It later issued a recall.
One analyst said GM appeared to be moving aggressively to address whatever problem it found in the Cruze.
"This could be an example of how the 'new' GM will handle potential safety issues moving forward," said Alec Gutierrez, an analyst with the auto research firm Kelley Blue Book. "They have decided to tackle the issue head-on to ensure potentially unsafe vehicles don't end up in the driveways of unsuspecting consumers."
Last year, the Cruze was GM's best-selling passenger car in the U.S., with sales of 248,000.