U.S. regulators are investigating Toyota Motor Corp.'s Camry and RAV4 vehicles following reports of electrical fires in driver-side doors.

The National Highway Traffic Safety Administration announced the inquiry into about 830,000 Camry cars and RAV4 crossover sport utility vehicles for the 2007 model year on its website Friday.

The agency said it has received six reports of fires that appear to have started in the power window's master switch on the driver's side.

"Toyota will fully cooperate with the agency in its efforts to investigate these allegations," said Martha Voss, a Washington-based spokeswoman for Toyota.

The carmaker, which is seeking its best U.S. sales in four years, last week said it's planning to deliver more units of the latest RAV4 model, Tacoma trucks and the SE grade of its new Camry sedan to American dealers to meet stronger-than-expected demand.