TOKYO (AP) — Toyota's president emerged from seclusion Friday to apologize and address criticism that the automaker mishandled a crisis over sticking gas pedals. Yet he stopped short of ordering a recall for the company's iconic Prius hybrid for braking problems.

Akio Toyoda, appointed to the top job at Toyota Motor Corp. last June, promised to beef up quality control, saying, "We are facing a crisis."

Toyoda, grandson of the company's founder, said he personally would head a special committee to review checks within the company, go over consumer complaints and listen to outside experts to come up with a fix.

"I apologize from the bottom of my heart for all the concern that we have given to so many customers," said Toyoda, speaking at his first news conference since the Jan. 21 global recall of 4.5 million vehicles.

Toyota's failure to stem its widening safety crisis has stunned consumers and experts who'd come to expect only streamlined efficiency from a company at the pinnacle of the global auto industry.

"Toyota needs to be more assertive in terms of providing consumers comfort that the immediate problem is being addressed ... and that it can deal with these crises," said Sherman Abe, a business professor at Hitotsubashi University in Tokyo.

It took prodding from the U.S. government for Toyota to recall the vehicles, about half of them in North America, for gas pedals that can stick and cause sudden acceleration.

Asked if he should have acted more quickly, Toyoda replied in hesitant English: "I will do my best."

Also on Friday, Safety Research and Strategies Inc. of Rehoboth, Mass., issued a report saying that Toyota and the government must look closely at vehicle electronics for a cause of sudden acceleration.

According to the report, there is evidence that Toyota and National Highway Traffic Safety Administration have not identified all causes of the problem, which they have blamed on sticky accelerators and floor mats that can bend on top of gas pedals and press them down.

NHTSA earlier this week began studying whether automobile engines could be disrupted by electromagnetic interference caused by power lines or other sources.

Safety Research and Strategies, which has received funding for research on Toyotas from five law firms, said the report released Friday was not paid for by attorneys with interest in the Toyota problems.

"Absent a mechanical cause, the automaker and the regulators must look more closely at the vehicle control systems, including the electronic throttle control design and the the associated sensors," the report says.

Toyota has said it investigated for electronic problems and failed to find a single case pointing that direction. The company says its systems have failsafe mechanisms.

Toyoda was the second successive Toyota president to offer an apology for defects in the company's cars. The first, Katsuaki Watanabe, shocked a news conference in 2006, bowing low to the group before promising to improve quality.

Toyoda bowed as he greeted reporters, but not in apology. He told the hastily called news conference that the company had not decided what to do about problems in the braking system of the Prius gas-electric hybrid. The high-mileage, low-pollution car is a leader in its field and a symbol of Toyota technology

Toyoda and Shinichi Sasaki, who oversees quality control, offered no new explanations for the braking problem.

Prius drivers in Japan and the U.S. have complained of a short delay before the brakes kick in — a flaw Toyota says can be fixed with a software programming change. The lag occurs as the car is switching between brakes for the gas engine and the electric motor — a process that is key to the hybrid's increased mileage.

Toyota spokesman Mike Michels said Friday the company continues to weigh options on how to handle repair of the problem, and it is communicating with the National Highway Traffic Safety Administration.

Among the options are a service campaign in which Toyota would notify owners to bring their cars in for repairs, or a full-fledged safety recall. Michels said he could not say when Toyota would make a decision.