(Reuters) — General Motors Co. suffered from "incompetence and neglect" in dealing with a long-running ignition-switch defect in vehicles linked to at least 13 deaths, CEO Mary Barra said Thursday as she announced the creation of a fund to compensate victims.

Ms. Barra said 15 employees found to have "acted inappropriately" have been fired. She did not name individuals.

Speaking at the company's technical center in Warren, Michigan, Ms. Barra addressed an estimated crowd of nearly 1,000 employees as the largest U.S. automaker unveiled the findings of an internal investigation into why it took more than a decade to finally recall vehicles with the safety defect.

While Ms. Barra noted a pattern of "incompetence and neglect" that she blamed on "individuals" who failed to "disclose critical pieces of information" about the ignition switches, she added that there was "no conspiracy by the corporation to cover up facts."

Furthermore, Ms. Barra said the internal investigation "found no evidence that any employee made a trade-off between safety and cost" in failing to deal with the safety problem.

With the release of GM's internal investigation, Congress is expected to announce a new round of hearings soon. In coming weeks, the company also might address whether it will establish a mechanism for compensating victims and their families.

But the internal probe found senior executives were not to blame for a delayed vehicle recall involving the defective ignition switches, a person familiar with the matter told Reuters on Thursday.

Ms. Barra, who has been CEO for only a few months, began her remarks with a message to victims' families.

She gave her "deepest sympathies to the families that lost loved ones and to those who were injured. I realize there are no words of mine that can ease their grief or their pain."

Her remarks were broadcast to GM's 220,000 workers globally.

The source confirmed that the report concluded that Ms. Barra, executives who reported directly to her, the board of directors and former CEO Dan Akerson did not know about the defective switches before December.

It also found that GM's general counsel, Michael Millikin, was not responsible for the mishandling of defects and the recall delay, the source said. Mr. Millikin, who led the internal probe with former U.S. prosecutor Anton Valukas, is expected to continue working at GM.

The move to spare top executives from blame drew some sharp criticism.

"How do you truly fix a culture of carelessness and cover-up without cutting the head off the snake?" said Robert Hilliard, a lawyer for a plaintiff in a lawsuit against GM related to the ignition switch defect.