WASHINGTON: US Transportation Secretary Anthony Foxx said his agency was looking into whether General Motors was slow to report to the federal government problems with ignition switches in its autos, which have led to 12 deaths.

"The questions we are asking are whether there was a timeliness issue with GM's bringing to our attention the issues regarding this ignition switch," Foxx told a Senate panel.

"Had we known there was an issue, that might have changed the outcome of those initial crash investigations" by the government, Foxx said.

Foxx said if there are delays in the industry reporting problems to the National Highway Traffic Safety Administration, the Transportation Department will respond in a "very, very tough" manner.

Democratic Senator Patty Murray, who chairs a Senate Appropriations panel with oversight of transportation funding, asked why it took almost a decade for GM to report safety problems that have resulted in 1.6 million auto recalls and whether the government must do more to bring about a better industry performance.

Foxx said the administration was conducting an "aggressive investigation."

"Despite three crash investigations and other research, the data was inconclusive," he said.

"It just didn't point to an investigation" by NHTSA initially."

The GM auto recalls cover cars models of varying ages, including some nearly 10 years old.

In response to consumer complaints several years ago about unintended acceleration in some Toyota vehicles, the US government toughened penalties for inadequate reporting by industry.