The National Highway Traffic Safety Administration's top official on Friday said there was no information that General Motors Co's Chief Executive Mary Barra knew about faulty ignition switches in some of the company's vehicles.

But other GM employees, from engineers to executives, were aware of the problem, acting administrator David Friedman told reporters at a news conference after U.S. transportation officials announced a $35 million penalty against the automaker.

"Their process was broken," Friedman said, adding that the company's recall problems were due to several factors.

(Reporting by Richard Cowan; Writing by Susan Heavey, Editing by Franklin Paul)