Two top General Motors executives have left the company in the wake of the ignition switch fiasco for undisclosed reasons.

Selim Bingol, formerly GM's senior vice president for global communications and public policy, and Melissa Howell, senior vice president for global human resources, are no longer working at GM, although the company hasn't specified if they resigned or were let go, The New York Times reported.

Their departures mark the first such shift since Barra took over as CEO in January and almost immediately had to deal with a 2.6-million vehicle recall that has been related to 13 deaths. The staff change was not connected to the recall involving defective ignition switches, GM spokesman Greg Martin told the Times.

Howell joined GM in 1990, rising to become its top executive in human resources last year, while Bingol was hired in 2010.

While Bingol's replacement has not yet been named, John J. Quattrone, a GM employee since 1975, has been promoted to fill Howell's spot. Quattrone, who has been heading the company's product development and purchasing divisions, has spent time in various roles in human resources and labor relations at GM.

"John brings to the job a deep and rich breadth of experience across all levels of the enterprise," Ms. Barra said in a statement quoted by the Times. "This background is invaluable as we create lasting change that puts the customer at the center of how we work and how we measure ourselves going forward."

Barra testified before the Senate earlier this month as part of the federal investigation of the recall but had little information to offer as to why millions of small cars weren't fixed years earlier.

GM has received criticism for failing to fire anyone in connection with the ignition switches, which were reported to be a problem at least a decade ago; however, the company did put two engineers on paid leave last week.

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