The Obama administration's bailouts for troubled automakers might have been conditioned on support for tougher fuel efficiency standards, top House Republicans said Thursday.

Rep. Darrell Issa (R-Calif.), the ranking member of the House Oversight and Government Reform Committee, and Rep. Lamar Smith (R-Texas), the ranking member of the House Judiciary Committee, wrote the chief executives of nine automakers to ask for answers as to whether or not they were pressured by the administration into supporting emissions standards.

Specifically, Issa sought answers into whether General Motors and Chrysler were pressured into supporting the new standards as a condition for receiving support during their government-supervised bankruptcies last year.

"It is unclear whether the Administration used leverage created by the possibility of a taxpayer bailout of GM and Chrysler to secure their cooperation and support for new fuel economy standards," Issa and Smith said in a statement. "Moreover, there is reason to believe Administration officials used inappropriate tactics to ensure broad based support across the industry."

The letter comes after General Motors repaid billions from those loans to the government well ahead of schedule, and Chrysler posted an operating profit for the first quarter of this year.

The White House eagerly promoted those news items as a validation of their decision to assist the automakers when they teetered on the brink of collapose last year.

The GOP congressman blasted the administration for not having responded to previous inquiries on the issue.

"Given the clear conflict-of-interest issues at play, which naturally arise when the government is in a position to pick winners and losers and impact the future viability of private entities, it was imperative that the Administration act with the utmost transparency," the pair said. "Instead, the White House imposed an unprecedented level of secrecy.”