General Motors is recalling almost 780,000 older-model compact cars in North America because a faulty ignition switch can shut off the engines without warning and cause crashes.

The company says six people have died in 22 crashes linked to the problem in Chevrolet Cobalts from the 2005 through 2007 model years, and Pontiac G5s from 2007.

A heavy key ring or jarring from rough roads can move the ignition switch out of the run position, cutting off the engine and electrical power, GM said in statements and documents released Thursday by the U.S. National Highway Traffic Safety Administration. If that happens, the air bags may not work if there’s a crash.

GM says the six people were killed in five front-end crashes, all of which happened off-road and at high speeds. In each case, the ignition switch moved out of the run position, shutting off the engine and electrical power, spokesman Alan Adler said. That condition would cause the loss of equipment such as power steering assist and power-assisted brakes, he said.

Alcohol was involved in three of the fatalities, and in some cases people weren’t wearing seat belts, Adler said.

Dealers will replace the ignition switch for free, but the timing of the recall hasn’t been finalized. Until the problem is fixed, GM is urging owners to remove nonessential items from key rings.

More than 619,000 of the cars in the recall were sold in the U.S., with another 153,000 in Canada and more than 6,000 in Mexico, according to the company. All but 33,000 of the cars to be recalled are Cobalts. The Pontiac G5 is nearly identical to the Cobalt.

(AP)