The National Highway Traffic Safety Administration this week sent a letter to Chrysler Group, urging the automaker to “more aggressively seek out vehicle owners” of recalled 2002-2007 Jeep Liberty and 1993-1998 Jeep Grand Cherokee SUVs whose fuel tanks are at risk for rupturing in rear crashes.

To address the resultant fire risk, Chrysler’s recall remedy involves reinforcing the rear structure of the vehicles through installation of a trailer hitch assembly. Back in July, federal regulators also criticized the pace of recall repairs. 

The new Nov. 19-dated letter, written by NHTSA Deputy Administrator David J. Friedman and addressed to Chrysler CEO Sergio Marchionne, cites a Chrysler recall update reporting a 3-percent repair completion rate for 1.56 million vehicles. Friedman characterizes this repair rate as “woeful” and also questions whether Chrysler dealers are hindering the recall effort.

“According to complaints received by NHTSA, owners are being turned away by Chrysler dealerships because of a lack of parts and, in some cases, are reportedly being told that their vehicles are safe to drive without the remedy,” Friedman says in the letter. “If these reports are at all accurate, the dealerships’ conduct is unacceptable.”

Friedman’s letter sets a Dec. 15 deadline for Chrysler to confirm that “its dealerships are giving owners accurate information and implementing the repairs in a timely and effective manner.” Additionally, Chrysler must provide NHTSA with a plan, also due Dec. 15, detailing how the automaker will contact and provide incentive for vehicle owners to get the recall repairs completed.

According to the Wall Street Journal, concerns about the pace of the SUV recall have resurfaced in part because of a collision earlier this month involving Kayla White, a pregnant 23-year-old who died when her 2003 Jeep Liberty was struck from behind and caught fire in Michigan.

On Nov. 20, a Chrysler representative told the Wall Street Journal that about 137,000 recalled Jeeps have already been inspected or repaired as part of the ongoing safety recall. About 488,000 repair parts are now in the hands of dealers. That means the repair rate has risen to nearly 9 percent since the last recall update submitted to NHTSA. 

The fuel tank issue has been linked to 51 fires resulting in fatalities, according to NHTSA. This particular recall has been fraught with conflict, with Chrysler initially refusing to comply with the agency’s recall request in 2013.