'I'm sorry,' Toyota boss tells world

Akio Toyoda also promised to strengthen quality control by setting up a special committee he would head himself.

He said the car maker was still deciding what to do to fix braking problems with Prius gas-electric hybrid, the world's biggest selling hybrid vehicle.

Mr Toyoda, the grandson of Toyota's founder, was speaking at a news conference in Nagoya, Japan.

Toyota has acknowledged the new Prius that went on sale in May last year has braking problems but Mr Toyoda did not announce a recall.

Some owners of the 2010 Prius have reported their brakes do not always engage immediately when they press the brake pedal.

The problem has been fixed with a software programming change for Prius vehicles sold in Japan and overseas since late January, but not for vehicles sold before then.

The firm has been criticised for failing to act sooner over safety problems which have also led to a recall of millions of vehicles because of accelerator pedals that can become stuck.