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A Texas lawyer is asking a federal judge to force General Motors to tell owners of 1.6 million recalled vehicles they should immediately stop driving those models. Attorney Robert Hilliard said people driving GM cars recalled for faulty ignition switches are putting themselves at risk if they continue operating their cars before they are fixed. "I believe it to be extremely dangerous not just for the people driving the vehicles, but for those driving around the vehicles," said Hilliard. Hilliard's motion calling for GM to issue a "Park it Now Alert" was filed in a U.S. District Court in Corpus Christi, Texas. GM said it stands by its recall, which says the recalled models are safe to use while awaiting repair, provided drivers have nothing hanging from the ignition key while operating the vehicle. Read MoreFierce headwinds: GM's past dragging on its future

The automaker blames the weight of keys, the key fob or other objects dangling from the key ring for causing the ignition switch to slip out of the run position while vehicles are in drive. The automaker said that slip in the switch can shut off power steering, brakes and air bags, leaving the driver and others in the car unprotected.

Just last week, GM CEO Mary Barra was asked if she feels it's still safe to drive the Chevy Cobalt, one of several models recalled.

"If you have just the ring with the key, it is safe to drive," said Barra. "The technical team has done extensive analysis for me to be able to make that claim and when they came back and reported that to me, my question was 'Would you let your wife drive that car?' and they said yes." Hilliard said that comment is outrageous. "You know there is not anyone that I know that would put a family member in it (a recalled GM vehicle) at all," he said.

One bump from an accident

Hilliard said GM's own recall notice makes it clear the potential for a deadly accident in a recalled vehicle awaiting repair is still substantial.

It warns owners of the recalled cars, "There is a risk, under certain conditions, that your ignition switch may move out of the 'run' position, resulting in a partial loss of electrical power and turning off the engine. This risk increases if your key ring is carrying added weight (such as more keys or the key fob) or your vehicle experiences rough road conditions or other jarring or impact related events." "They are telling their customers if they hit a bump in the road this could happen," said Hilliard. "Even if you follow their instruction as to removing the extra weight from the keychain, the vehicle could go in the auxiliary mode and you could lose braking, you lose power and you lose the protection of the airbag." Read MoreCar safety agency asleep at wheel: Critics

Hilliard represents 52 owners of GM vehicles, including the families of 13 people he says were killed in accidents linked to the faulty ignition switches. General Motors said it stands behind the recall of the 1.6 million models built between 2003 and 2007. It said there are no plans to change the warning to drivers about using only the ignition key.

Park it now alerts rare