GM boss Mary Barra 'deeply sorry' for ignition fault
General Motors chief executive Mary Barra has apologised for an ignition switch fault in some cars linked to at least a dozen deaths in road crashes.
At a US congressional hearing on Tuesday, she also said she was "disturbed" by the company's previous comments about the high cost of replacing the defective parts.
General Motors (GM) has so far recalled 2.6m cars because of the defect.
But it has been criticised for taking too long to do so.
Faults with ignition switches in some GM models, including the Chevrolet Cobalt and Saturn Ion, were first reported more than 10 years ago.
But the company only began recalling vehicles in February this year, a month after Ms Barra took over as chief executive.
"I cannot tell you why it took years for a safety defect to be announced... but I can tell you that we will find out," said Ms Barra, testifying before a US House of Representatives panel investigating the issue.
"As soon as l learned about the problem, we acted without hesitation. We told the world we had a problem that needed to be fixed.
"We did so because whatever mistakes were made in the past, we will not shirk from our responsibilities now and in the future. Today's GM will do the right thing.
"That begins with my sincere apologies to everyone who has been affected by this recall, especially to the families and friends of those who lost their lives or were injured.
"I am deeply sorry."
Ms Barra said she found it "disturbing" that cost considerations may have discouraged an immediate replacement of the faulty switches.
The chairman of the House Energy and Commerce Committee, Republican Fred Upton, told Ms Barra: "With a two-tonne piece of high-velocity machinery, there is zero margin for error; product safety is a life or death issue.
"But sadly, vehicle safety has fallen short."
GM's initial recall affected 1.6 million cars made before 2007, and last week the company announced it would also cover more than 800,000 made from 2008-11.
At issue is a flaw in the manufacture of the ignition switch that causes the key to shift on its own from the "run" position to the "accessory" or "off position", even while the car is at full speed.
GM has launched an internal investigation into the matter, and last month created a new senior post to oversee vehicle safety and recalls.
And in the first hint that victims may be compensated, Ms Barra said GM would bring in consultant Kenneth Feinberg to help the company plan what to do "for those who suffered the most from this tragedy".
Mr Feinberg handled compensation issues related to the attacks in the US on 11 September 2001, the BP oil spill in the Gulf of Mexico, and last year's Boston Marathon bombing.
On Monday GM announced a separate recall of more than 1.3 million vehicles because of an electronic power steering threat which, it said, "could increase the risk of a crash".