U.S. government accuses Fiat Chrysler of cheating emission laws.

U.S. regulators blamed Fiat Chrysler Automobiles for violating emission standards in more than 100,000 diesel vehicles.

The Environmental Protection Agency claimed Fiat Chrysler placed software in Jeep Grand Cherokee and Ram 1500 models that permits them to surpass pollution limits.

Fiat Chrysler CEO Sergio Marchionne denied that the company was cheating.

“We have done nothing that is illegal,” he said. “There was never any intent of creating conditions that were designed to defeat the testing process. This is absolute nonsense.”

In a release, Fiat Chrysler responded by saying it is “disappointed” that the EPA issued the notice of violation. The automaker said it intends to work with the incoming administration to present its case “and resolve this matter fairly and equitably” and to prove to the regulator and its customers that its trucks meet environmental requirements.

“FCA US believes that its emission control systems meet the applicable requirements,” the company said.

The EPA is claiming that the undisclosed software brings about expanded emissions of nitrogen oxides from the vehicles.

“Failing to disclose software that affects emissions in a vehicle’s engine is a serious violation of the law, which can result in harmful pollution in the air we breathe,” Cynthia Giles, assistant administrator for EPA’s enforcement unit, said in a release.

“We continue to investigate the nature and impact of these devices. All automakers must play by the same rules, and we will continue to hold companies accountable that gain an unfair and illegal competitive advantage,” she said.

“However, under some other kinds of operating conditions, including many that occur frequently in normal driving, the software directs the emission control system to operate differently, resulting in emissions that can be much higher,” she said. “For example, the software reduces the effectiveness of emissions controls when driving at high speeds and for an extended period.

Fiat Chrysler said it has already proposed actions to address the EPA’s concerns, “including developing extensive software changes to our emissions control strategies that could be implemented in these vehicles immediately to further improve emissions performance.”

The EPA has the authority to fine automakers up to $44,539 per vehicle for the most exceedingly terrible violations of the Clean Air Act. The office undermined possible fines Thursday on the off chance that it discovers that the software installed on the vehicles qualifies as illegal “defeat devices” under U.S. laws.

Fiat Chrysler sharestrading on the New York Stock Exchange were down around 10%.