(Adds GM comment In paragraphs 5-6)
WASHINGTON, April 22 (Reuters) - Former General Motors Co chief executives should be called to testify to the U.S. Congress about the company's slow response to defective ignition switches in cars that have been linked to at least 13 deaths, a Democratic senator said on Tuesday.
Senator Richard Blumenthal of Connecticut, an outspoken member of the Senate Commerce Committee that is investigating GM, said there are "a whole set of questions on why there were so many delays in taking action to remedy this situation" that are still unanswered by the Detroit automaker.
"Of course we have to go back to the prior CEOs" who headed GM before this year's recall of 2.6 million automobiles, he said. The recalled vehicles have ignition switches that can unexpectedly slip out of the "run" position, shutting off engines, disabling air bags, power steering and power brakes.
In a telephone interview with Reuters, Blumenthal stressed that it will be up to Senator Claire McCaskill, chairwoman of a commerce subcommittee, to schedule the next hearings and decide who will testify.
Asked about Blumenthal's interest in getting testimony of former chief executives, GM spokesman James Cain repeated an earlier statement that the company's senior leadership team was not aware of the recall decision until Jan. 31 of this year. He added that an internal investigation into the handling of the ignition switch problem is under way.
"When the facts are in, we will be transparent and hold ourselves accountable," Cain said.
Blumenthal added that "very definitely I want to hear" from former GM CEO Daniel Akerson, who held the post from 2010 until early this year when current CEO Mary Barra took over. During that time, GM was conducting internal investigations into the defective part.
Separately, GM announced on Tuesday that it is restructuring its engineering operations in a move meant to improve quality and safety of its vehicles, and that its global vehicle engineering chief, John Calabrese, is retiring.
Barra testified to the Senate panel on April 2, and to a House of Representatives subcommittee on April 1. She said she would be willing to return to Capitol Hill for more testimony.
Barra frustrated many members of Congress by testifying that she could not answer their questions because she is so new in the job, after decades of holding other positions within GM.
GM engineers first noticed problems more than a decade ago with ignition switches in Chevrolet Cobalts, Saturn Ions and other GM models but did not notify consumers until this year.
(Reporting By Richard Cowan; Editing by Karey Van Hall, Peter Henderson and Mohammad Zargham)