The spokeswoman, Sharon Paul, confirmed that federal law enforcement activity was conducted at locations in Peoria, East Peoria and Morton.

It was not immediately clear why federal agents raided the three locations.

Caterpillar spokeswoman Corrie Scott said in an emailed statement that the company was cooperating with authorities.

“Law enforcement is present in various Peoria-area Caterpillar facilities executing a search warrant. Caterpillar is cooperating,” Scott said. She declined to comment further.

Caterpillar shares fell 4.9% in afternoon trading on the news.

Agencies involved in the search included the Internal Revenue Service’s Criminal Investigation Division, the U.S. Department of Commerce’s Bureau of Industry and Security’s Office of Export Enforcement, and the Federal Deposit Insurance Corp.’s Office of Inspector General, the U.S. Attorney Office’s Paul said.

The facility in Morton, according to the company’s website, is responsible for receiving and shipping replacement parts to parts facilities and Caterpillar dealers worldwide.

Seven people, all wearing dark colored jackets marked either “IRS special agent” or “Police federal agents,” entered the Caterpillar headquarters, according to a video posted by the Peoria Journal Star. Several of the agents were armed, while others were pulling large black roller bags as they entered the building.

Caterpillar reported sales fell 18 percent in 2016 to $38.5 billion and since late 2015 it has shrunk its workforce by more than 16,000 employees and consolidated or closed 30 facilities. Caterpillarcut 12,300 jobs in 2016, including 7,700 in the United States.

It said it was considering closing two more major production facilities, including one in Aurora, Illinois, and also announced it was moving its corporate headquarters from Peoria to Chicago.