NHTSA posted two new U.S. Fiat-Chrysler recalls on Thursday morning.
Fiat-Chrysler is the first of several automakers to reveal which vehicle models are being added to the massive recall, following an announcement last week that defective Takata airbags may be installed in nearly 34 million vehicles from 11 manufacturers.
At least six deaths and more than 100 injuries have been linked to Takata airbag ruptures.
"NHTSA has received the list of vehicles from Fiat-Chrysler that are affected by the recent expansion of the Takata airbag recalls," according to a statement posted on the NHTSA Web site. "The vehicle identification numbers (VINs) included in these recalls are not yet available on NHTSA's VIN look-up tool or the manufacturer's Web site, but NHTSA will continue to provide updates as this information becomes available.
"If your vehicle is affected by this recall, follow up with the manufacturer to get interim guidance."
The larger Fiat-Chrysler recall announced on Thursday involves 4,066,732 vehicles.
They include the 2005-'09 Dodge Ram 2500; 2004-'08 Dodge Ram 1500 and Durango; 2006-'09 Dodge Ram 3500; 2008-'10 Dodge Ram 4500 and 5500; 2008-'09 Sterling Bullet 4500 and 5500; 2007-'08 Chrysler Aspen; 2005-'10 Chrysler 300, 300C, SRT8, Dodge Charger and Magnum; 2005-'11 Dodge Dakota; and 2006-'10 Mitsubishi Raider.
"In the event of a crash necessitating deployment of the driver's frontal airbag, the inflator could rupture with metal fragments striking and potentially seriously injuring the driver or other occupants," NHTSA said in its recall summary.
Federal safety regulators say that this recall supersedes a December 24, 2014 Fiat-Chrysler recall that included 2.9 million vehicles for defective Takata airbags.
"Vehicles that have had their driver-side frontal airbag replaced previously need to have their airbag replaced under this recall as well," NHTSA said.
However, Fiat-Chrysler has not provided an owner notification schedule yet. A Fiat-Chrysler document filed with NHTSA said: "At this time, the remedy component has yet to be determined."
A second Fiat-Chrysler recall for defective Takata passenger frontal airbags posted on Thursday covers another 438,156 vehicles.
This recall includes the 2003 Dodge Ram 1500, 2500 and 3500 built from January 1, 2002 to July 25, 2003.
"This recall addresses both the passenger-side frontal airbags that were originally installed in the vehicles, as well as replacement airbags that may have been installed as replacement service parts," NHTSA said.
This recall "partially supersedes" a December 3, 2014 recall of Fiat-Chrysler vehicles.
Dodge dealers will replace the passenger's frontal airbag in the second recall. A date has not been set for the recall.
Fiat-Chrysler spokesman Eric Mayne told Edmunds there are "no injuries, crashes or fatalities associated with the additional vehicles."
Owners can also contact NHTSA's Vehicle Safety Hotline at 1-888-327-4236.
Edmunds says: Since there is incomplete information about this expanded Fiat-Chrysler recall, affected consumers should stay in touch with the manufacturer and dealers for up-to-date information.