NEW YORK (Reuters) - Leading road travel group AAA on Friday called on the U.S. government to suspend the sale of gasoline with a higher blend of ethanol fuel, the latest opposition against increasing the use of biofuels in transport.

A lack of public awareness about the risks of using 15 percent ethanol, known as E15, in older cars could cause problems for motorists, according to an AAA study published Friday. The current standard is 10 percent, or E10.

The Environmental Protection Agency approved E15 in 2011 for cars and light trucks made since model year 2000, spurring opposition from auto-makers, service station owners and oil refiners who fear it may damage older engines, leaving them exposed to legal action from motorists.

Only about 5 percent of the 240 million light duty vehicles on U.S. roads today are approved by manufacturers to run on the E15, AAA said.

"AAA is urging regulators and the industry to stop the sale of E15 until motorists are better protected," AAA said in a statement.

E15 is barred from use in light equipment or older vehicles.

Biofuels makers sought the higher blend as a way to satisfy the federal Renewable Fuels Standard (RFS), which requires the use of 13.2 billion gallons of ethanol in fuel this year, rising to 15 billion gallons annually from 2015.

Currently only about ten stations in the United States offer E15, but AAA wants the suspension before next year, when the rising RFS mandate could force refiners and fuel blenders to increase the share of ethanol or face fines.

Governors of four poultry-raising states this year asked EPA for relief from the mandate, saying the corn crop is too small to use 40 percent of it making biofuels. Foodmakers, automakers and oil refiners also opposed it in court, though they lost.

"Unsuspecting consumers using E15 could end up with engine problems that might not be covered by their vehicles' warranties," AAA said.

It said that five manufacturers - BMW, Chrysler, Nissan, Toyota and Volkswagen - have said that their warranties will not cover fuel-related claims caused by the use of E15.

(Reporting By Edward McAllister; Editing by Bob Burgdorfer)