The previous recall was limited to Florida, Hawaii, Puerto Rico and several other territories. It now covers adjacent counties in southern Georgia, as well as the coastal areas of Alabama, Louisiana, Mississippi and Texas.
"We expect the total number affected to rise from 17,000 to 28,000," said Subaru spokesman Michael McHale, in response to an Edmunds query.
McHale said there are no injuries, crashes or fatalities linked to the recall.
"Upon deployment of the passenger side frontal airbag, excessive internal pressure may cause the inflator to rupture," said NHTSA in its recall summary on Monday. "In the event of a crash necessitating deployment of the passenger side frontal airbag, the inflator could rupture with metal fragments striking and potentially seriously injuring the vehicle occupants."
Owners can contact Subaru at 1-800-782-2783 and Saab at 1-800-955-9007.
Edmunds says: Owners should watch for an official recall notice and then schedule service. But if you own one of these vehicles and have an immediate concern, contact your dealer.