Washington » Reacting to Toyota Motor Corp.'s decision to recall 2010 Prius and Lexus hybrids, the National Highway Traffic Safety Administration advised owners Tuesday of the affected vehicles to contact a dealer immediately if they noticed a change in the performance of their brakes.

"Loss of braking is most likely to occur when traveling over an uneven road surface, pothole or bump," the agency said in a statement. "If this occurs, the agency advises owners to continue to firmly press on the brake to stop the vehicle. As an extra precaution, drivers can leave extra stopping distance."

The NHTSA announced last week it was opening a formal investigation into braking problems with the 2010 Prius hybrid after receiving 124 complaints about momentary loss of braking ability. Four of the complaints alleged the problems caused crashes. The agency said Tuesday that its investigators had spoken with consumers about the complaints as their investigation began.

The agency also said it was reviewing complaints about steering problems in the 2009 and 2010 Toyota Corolla after an analysis by Automotive News found an increase in such complaints after the model switched from hydraulic to electric power steering. NHTSA received 67 complaints about steering in the 2009 Corolla and 17 in the 2010 Corolla, according to the agency's database.

Toyota has recalled more than 8 million vehicles worldwide in recent months after reports of unintended acceleration, which the automaker has blamed on gas pedals that stick and on floor mats that can entrap the gas pedal. Some safety experts believe the issue could be with the electronic throttle control system in the vehicles, a claim that Toyota has refuted.

Late Monday, Toyota said it was recalling an additional 437,000 vehicles, including 133,000 Prius and 14,500 Lexus models in the United States, because of a braking problem. Owners will receive letters starting next week instructing them to bring the vehicles to a dealership to update software in the anti-lock brake system.

Transportation Secretary Ray LaHood said Tuesday that U.S. officials would continue to press the Japanese automaker to address safety concerns.

U.S. transportation officials have come under fire, along with Toyota, for not reacting more quickly to concerns about sudden acceleration problems in Toyota vehicles. A congressional committee had been scheduled to grill Toyota and U.S. officials on Wednesday about the safety problems.