WASHINGTON — A group of Republican former Environmental Protection Agency administrators, governors and members of Congress are throwing their public support behind a fuel economy target of 60 miles per gallon by 2025.

In a letter to President Barack Obama, the 15 signatories say that to reduce dependence on foreign oil and maintain a clean environment, upcoming Corporate Average Fuel Economy standards for 2017 to 2025 should be “aggressive” in order to achieve those goals.

“Strong, forward-looking standards for new vehicle fuel efficiency and emissions will provide industry with needed certainty for investment in new technologies while also driving reductions in oil consumption and carbon pollution that fuels climate change,” the letter states.

The group of Republicans say improvement of 6 percent annually in CAFE standards is “achievable and cost-effective for consumers.”

Six percent translates to about 60 miles per gallon by 2025, and is the target sought by many in the EPA itself and environmental groups. A proposed rule on the new 2017 to 2025 CAFE standards is set to be announced at the end of the summer, and the maneuvering behind the scenes is already in full swing this summer.

Auto companies and some business organizations are seeking a lower target for fear of hurting the auto industry. Automakers, however, are also pushing hard for one “national standard” when the proposed rules are announced in late summer — to avoid states like California instituting their own higher targets.

The 15 Republicans said they supported such a single national standard, but one set to hit the higher number of 60 miles per gallon by 2025.

“We recommend that you promulgate aggressive standards for the 2017 to 2025 vehicles under a national program,” they wrote.

Included in the group are former EPA administrators who worked under presidents Richard Nixon, Gerald Ford, Ronald Reagan, George H.W. Bush and George W. Bush.