Fiat Chrysler could face a fine of up to $4.6bn after the US Environmental Protection Agency accused the company of violating emissions laws in 104,000 diesel vehicles, only a day after Volkswagen agreed to pay a $4.3bn criminal fine for deliberately evading US pollution laws.

The move comes in the last days before Donald Trump assumes the presidency, signalling a determination on the part of Obama-era regulators to be as tough as possible on emissions violations before new appointees take office.

Sergio Marchionne, chief executive of Fiat Chrysler, denied the allegations and accused the EPA of “grandstanding” by announcing the charges only a week before Mr Trump takes office. “We have done nothing that is illegal,” he said, adding there were no similarities between his company’s behaviour and VW’s. “They [the EPA] think we all belong to a class of criminals?.?.?.?We’re not trying to break the bloody law.”