DETROIT -

General Motors is recalling millions of more vehicles for more ignition problems.

The automaker on Monday said it had six new safety recalls affecting 7.6 million vehicles in the U.S. from the 1997 to 2014 model years. Worldwide, the recalls include 8.4 million vehicles, bringing GM's 2014 recall total to 28 million vehicles.

View: List of GM recalls announced June 30

“We undertook what I believe is the most comprehensive safety review in the history of our company because nothing is more important than the safety of our customers,” said GM CEO Mary Barra. “Our customers deserve more than we delivered in these vehicles. That has hardened my resolve to set a new industry standard for vehicle safety, quality and excellence.”

Among these recalled vehicles, GM is aware of seven crashes, eight injuries and three fatalities. The fatal crashes occurred in older model full-size sedans being recalled for inadvertent ignition key rotation. There is no conclusive evidence that the defect condition caused those crashes.

"We have worked aggressively to identify and address the major outstanding issues that could impact the safety of our customers,” Barra said. “If any other issues come to our attention, we will act appropriately and without hesitation.”

GM expects to take a charge of up to approximately $1.2 billion in the second quarter for the cost of recall-related repairs announced in the quarter. This amount includes a previously disclosed $700 million charge for recalls already announced during the quarter.

Until the ignition recall repairs have been performed, it is very important that customers remove all items from their key ring, leaving only the vehicle key, and always use their seat belts. The key fob, if present, should also be removed from the key ring.

Read: GM won't limit ignition switch crash compensation

Complete coverage: GM ignition switch recall investigation