The Justice Department is investigating claims of anticompetitive behavior by shipping companies FedEx Corp. and UPS Inc.

Los Angeles antitrust attorney Maxwell Blecher said in a sworn court document filed last month that on Nov. 22 a trial attorney in the Justice Department's antitrust division called him and said they had begun a formal investigation of UPS and FedEx.

The Justice Department declined to confirm the investigation on Friday. FedEx and UPS say they are aware of the investigation.

Blecher represents a firm called AFMS Logistics Management Group that helps companies negotiate lower rates from UPS and FedEx. The company's federal lawsuit accuses UPS and FedEx of announcing on the same day that they would no longer deal with such consultants. Blecher said on Friday that the moves were "devastating" for AFMS's business.

AFMS is "keeping the doors open, but it's not easy," he said.

UPS spokeswoman Susan Rosenberg said the company is cooperating with the civil investigation. The company's position is that it has a right to decline to do business with third-party negotiators such as AFMS, she said.

FedEx spokesman Maury Lane said the investigation began after Blecher asked the government to look into the allegations.

Both companies have asked a federal judge to dismiss AFMS's claims. A hearing is planned for Jan. 31 in Los Angeles.

UPS shares fell 34 cents to close at $72.15, while FedEx shares rose 5 cents to close at $93.15.