CHICAGO (AFP) ― General Motors on Tuesday significantly expanded the recall of vehicles found to have an ignition defect that can cause them to suddenly turn off, a problem linked to 13 deaths.

The largest U.S. automaker will now recall 1.6 million vehicles in the United States, Canada and Mexico.

The original recall, issued about two weeks ago for nearly 780,000 vehicles, was linked to 22 crashes where the front seat airbags did not deploy, and six deaths.

The defect stems from a weakness in the ignition switch that could allow a heavy set of keys to switch it into the “accessory” or “off” position, particularly if the vehicle experiences a sudden jolt.

GM said in the intial recall that the five crashes which claimed the lives of six people “occurred off-road and at high speeds, where the probability of serious or fatal injuries was high regardless of airbag deployment.”

Further review raised the total to 31 crashes in which the defect may have stopped the airbags from deploying, and 13 deaths.

The recall now totals 1.4 million vehicles in the United States, while nearly 236,000 were recalled in Canada and about 9,000 in Mexico.

The initial investigation was “not as robust as it should have been” and GM is determined to improve its handling of reported problems, GM North America President Alan Batey said in a statement.

“Ensuring our customers’ safety is our first order of business,” Batey said. “We are deeply sorry and we are working to address this issue as quickly as we can.”

The company said it will aggressively seek out owners to alert them to the risk and get them to bring their vehicles into a dealership where the repairs will be performed free of charge.

The recall affects the following vehicles: model years 2005-2007 Chevrolet Cobalts, Pontiac G5 and Pontiac Pursuit; 2003-2007 Saturn Ions; 2006-2007 Chevrolet HHRs; and 2006-2007 Pontiac Solstice and Saturn Sky models.