Fiat Chrysler Automobiles NV has received subpoenas from U.S. federal and state authorities, including the Securities and Exchange Commission, related to alleged excess diesel emissions by some of its vehicles, the automaker reportedly said in a filing with the SEC on February 28.

The Reuters news agency says that on the diesel emissions issue, FCA said it has "received various inquiries, subpoenas and requests for information from a number of governmental authorities, including the U.S. Department of Justice, the SEC and several states’ attorneys general. We are investigating these matters and we intend to cooperate with all valid governmental requests," FCA reportedly said in its annual report filed with the SEC.

Reuters says that earlier in February, a person briefed on the matter said the Justice Department has been involved in the matter for more than six months after getting a referral from the Environmental Protection Agency in July. Involvement by the SEC and state attorneys general has not been previously disclosed.

FCA said Jan. 12 that the Justice Department was investigating the matter, Reuters says.

In January, the EPA said the maximum possible fine against FCA could be $4.6 billion.