The U.S. government said on Monday that it will seek as much as 16.375 million dollars of civil penalty against Toyota over the massive recalls.

"We now have proof that Toyota failed to live up to its legal obligations," said U.S. Transportation Secretary Ray LaHood.

"Worse yet, they knowingly hid a dangerous defect for months from U.S. officials and did not take action to protect millions of drivers and their families," he said. "For those reasons, we are seeking the maximum penalty possible under current laws."

The fine would be the largest civil penalty assessed by the U.S. government against an automaker. Toyota has two weeks to respond to the proposed fine.

Automakers are required to notify U.S. regulators of a possible defect with five business days.

But U.S. officials said that Toyota failed to notify the National Highway Traffic Safety Administration (NHTSA), the U.S. auto safety agency of the dangerous "sticky pedal" defect for at least four months, despite knowing of the potential risk to consumers.

"Safety is our top priority and we will vigorously pursue companies that put consumers at risk," said NHTSA Administrator David Strickland. "We will continue to hold Toyota accountable for any additional violations we find in our ongoing investigation."

Approximately 2.3 million vehicles in the U.S. were recalled in late January for the sticky pedal defect.

The company has recalled more than 6 million vehicles in the U. S., and more than 8 million worldwide for flaws that may cause unintended acceleration problems.