The clash between Chrysler Group and the National Highway Traffic Safety Administration over the recall involving 1993-2004 Jeep Grand Cherokees and 2002-2007 Jeep Liberty vehicles took another turn on Wednesday.

NHTSA officials issued a special order because they want to know why it’s taking what they consider to be a long time to repair 1.56 million vehicles in a recall that was announced last June. According to a NHTSA document from June 2012, the Office of Defects Investigation opened an analysis to investigate an alleged safety-related defect concerning fuel-tank system integrity in rear impacts or crashes in these SUVs.

The investigation revealed “numerous fire-related deaths and injuries, fires that did not result in deaths and fuel leaks in rear impacts.” NHTSA contends that the vehicles in question pose a risk to motor vehicle safety in rear-impact collisions due to possible malfunctions in the fuel systems.

Regulators wanted Chrysler to recall more than 2.7 million units, but the agency and the automaker agreed last June that a recall campaign would cover less than that amount.

But now, NHTSA is wary the OEM doesn’t have the parts to make these repairs at franchised dealerships. Regulators now are seeking answers to eight different questions, including data about how many of these units still are in operation, the rate repairs are being made and how additional parts are being manufactured.

Chrysler faces a deadline of July 16 to submit affidavits and other materials; otherwise, the automaker faces a $7,000 per day fine from NHTSA that can climb up to $35 million.

“NHTSA is therefore concerned that Chrysler does not have, and will not have, sufficient production capacity to ensure that enough hitches will be available to ensure that the recalled vehicles will be remedied expeditiously,” officials said in the special order to Chrysler. “For many owners, a recall remedy deferred by parts availability easily becomes a defect remedy denied. Moreover, additional delays in implementing this recall will inure to Chrysler’s benefit at the expense of vehicle owner safety.

“Although NHTSA acknowledges that recall campaigns may have low completion rates for any number of reasons, the agency has no intention of allowing Chrysler, or any other manufacturer, to delay recall completion to the detriment of safety,” officials continued. “NHTSA is therefore issuing this special order to obtain information regarding Chrysler’s data collection, planning and decision-making in regard to its implementation of the recall remedy in this case.”

In a message to Auto Remarketing, Chrysler said it welcomes the findings of NHTSA pertaining to the safety of these vehicles.

“According to the agency, after conducting and analyzing eight rear impact crash reconstruction tests, NHTSA informed Chrysler that ‘it did not have any reservations about implementation of Chrysler’s proposed remedy.’ This reflect Chrysler Group’s longstanding position — supported in the public record by real-world data — that the vehicles are not defective. They are among the safest in their peer groups and met or exceeded the standards in effect at time they were first sold. We remain unwavering in our commitment to design, engineer and build vehicles that afford outstanding customer safety and security.”

Chrysler insisted that this campaign has been conducted in close coordination with NHTSA.

“The agency has had full knowledge of our activities. Chrysler Group complied with all applicable regulations governing recalls, and has been working with NHTSA all along in this process,” OEM officials said.

Chrysler went on to mention that launching a safety recall demands complex engineering and close coordination with NHTSA well before an automaker accumulates replacement parts.

“To accommodate the high-volume production required for this campaign, Chrysler Group had to find and enlist multiple new supplier partners to supply volume of this part that far exceeded normal demand,” the company said.

“Parts production has commenced. Our supplier partners are committed to a work schedule of three shifts per day, six days per week, with occasional Sunday production,” the automaker added.

“Chrysler Group has already contacted affected customers and advised them of our intentions. They will be contacted again when the time is appropriate to schedule service. The cost of this work will be borne by the company,” the OEM concluded.