Government safety regulators have expanded an investigation into fires in older-model Jeep Grand Cherokees.
The National Highway Traffic Safety Administration says on its website that it has added Jeep Liberty and Cherokee SUVs to the investigation. The probe now covers 5.1 million vehicles. The agency says 15 people have died in 26 Grand Cherokee fires.
The government started investigating nearly two years ago. It's looking at complaints that gas tanks can leak and cause fires after rear-end crashes.
The investigation affects 1993 to 2004 Grand Cherokees. Also covered are 1993-2001 Cherokees and 2002-2007 Libertys. All three have gas tanks under the rear bumpers.
The SUVs haven't been recalled. Chrysler says the vehicles are safe and meet federal safety standards. It says fires after rear-end crashes involving Grand Cherokees are rare.